i2ceeprom, actually add the device
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dinkc64
parent
37b23ddfac
commit
31e1027b25
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#include "burnint.h"
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#include "i2ceeprom.h"
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// i2c eeprom / e2prom - dink 2025
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struct i2c_device_struct {
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int id;
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int size;
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int pagemask;
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};
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static i2c_device_struct i2c_devices[] = {
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{ I2C_NONE, 0x00, 0x0 },
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{ I2C_24C01, 0x80, 0x4-1 },
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{ I2C_X24C01, 0x80, 0x4-1 },
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{ I2C_X24C02, 0x100, 0x4-1 },
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{ I2C_24C02, 0x100, 0x4-1 },
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{ I2C_24C04, 0x200, 0x10-1 },
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{ I2C_24C08, 0x400, 0x10-1 },
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{ I2C_24C16, 0x800, 0x10-1 },
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{ I2C_24C32, 0x1000, 0x20-1 },
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{ I2C_24C64, 0x2000, 0x20-1 },
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{ I2C_24C128, 0x4000, 0x40-1 },
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{ I2C_24C256, 0x8000, 0x40-1 },
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};
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enum {
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I2C_STOP = 0,
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I2C_DEVICEID,
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I2C_ADDR,
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I2C_ADDR_EXT,
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I2C_WRITE,
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I2C_READ
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};
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// config
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static UINT16 i2c_device = 0;
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static UINT16 i2c_mask;
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static UINT16 i2c_page_mask;
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static bool uses_bus;
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// e2prom internals
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static UINT8 *i2c_memory;
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static int i2c_mode;
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static UINT16 i2c_address;
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static UINT8 i2c_shifter;
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static INT8 i2c_bit_count;
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static UINT8 i2c_selected_device;
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static bool i2c_sda, i2c_scl;
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static bool i2c_sda_read;
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// bus interfacing
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static UINT8 sda_bit, scl_bit, sda_read_bit;
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static UINT8 bus_buffer[2];
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#define bus_debug 0
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#define device_debug 1
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void i2c_write_bus16(UINT32 data) {
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const UINT8 scl = (data >> scl_bit) & 1;
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const UINT8 sda = (data >> sda_bit) & 1;
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if (bus_debug) bprintf(0, _T("wb16 %x, scl/sda: %x %x\n"), data, scl, sda);
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i2c_write_bit(sda, scl);
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}
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void i2c_write_bus8(UINT32 address, UINT8 data) {
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if (bus_debug) bprintf(0, _T("wb8 %x %x\n"), address, data);
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bus_buffer[address & 1] = data;
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i2c_write_bus16(bus_buffer[0] << 8 | bus_buffer[1]);
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}
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UINT32 i2c_read_bus16(UINT32 address) {
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const UINT32 data = i2c_read() << sda_read_bit;
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if (bus_debug) bprintf(0, _T("rb16 %x, sda %x\n"), address, data);
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return data;
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}
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UINT32 i2c_read_bus8(UINT32 address) {
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const UINT32 data = i2c_read_bus16(address) >> ((~address & 1) << 3);
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if (bus_debug) bprintf(0, _T("rb8 %x %x\n"), address, data);
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return data;
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}
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void i2c_init(UINT8 device, UINT8 sda, UINT8 scl, UINT8 sda_read) {
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i2c_init(device);
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uses_bus = true;
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sda_bit = sda;
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scl_bit = scl;
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sda_read_bit = sda_read;
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}
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void i2c_init(UINT8 device) {
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if (device == I2C_NONE) return;
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i2c_device = device;
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i2c_mask = i2c_devices[i2c_device].size - 1;
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i2c_page_mask = i2c_devices[i2c_device].pagemask;
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i2c_memory = (UINT8*)BurnMalloc(i2c_devices[i2c_device].size);
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memset(i2c_memory, 0xff, i2c_devices[i2c_device].size);
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}
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void i2c_exit() {
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BurnFree(i2c_memory);
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uses_bus = false;
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i2c_device = I2C_NONE;
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}
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void i2c_scan(INT32 nAction, INT32 *pnMin) {
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if (i2c_device == I2C_NONE) return;
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if (nAction & ACB_VOLATILE) {
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SCAN_VAR(i2c_mode);
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SCAN_VAR(i2c_address);
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SCAN_VAR(i2c_shifter);
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SCAN_VAR(i2c_bit_count);
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SCAN_VAR(i2c_selected_device);
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SCAN_VAR(i2c_sda);
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SCAN_VAR(i2c_scl);
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SCAN_VAR(i2c_sda_read);
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if (uses_bus) {
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SCAN_VAR(bus_buffer);
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}
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}
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if (nAction & ACB_NVRAM) {
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ScanVar(i2c_memory, i2c_devices[i2c_device].size, "NV RAM");
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}
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}
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void i2c_reset() {
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i2c_mode = I2C_STOP;
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i2c_address = 0;
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i2c_shifter = 0;
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i2c_bit_count = 0;
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i2c_selected_device = 0;
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i2c_sda = i2c_scl = 1;
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i2c_sda_read = 1;
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bus_buffer[0] = bus_buffer[1] = 0xff;
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}
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bool i2c_read() {
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return (i2c_mode == I2C_STOP) ? i2c_sda : i2c_sda_read;
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}
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void i2c_write_bit(bool sda, bool scl) {
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if (sda != i2c_sda && (scl && i2c_scl)) {
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// start / stop condition: when sda toggles while scl remains high
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// sda, high to low: start
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// sda, low to high: stop
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i2c_mode = (sda) ? I2C_STOP : I2C_DEVICEID;
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if (device_debug)
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bprintf(0, _T("%S condition.\n"), (i2c_mode == I2C_DEVICEID) ? "START":"STOP");
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i2c_bit_count = 0;
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i2c_shifter = 0;
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i2c_sda = sda;
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i2c_scl = scl;
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return;
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}
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if (!i2c_scl && scl && i2c_mode != I2C_STOP) {
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if (i2c_mode != I2C_READ) {
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// when not in READ mode, we're shifting bits into the shifter
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if (i2c_bit_count < 8) {
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i2c_shifter = (i2c_shifter << 1) | sda;
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}
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i2c_bit_count++;
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}
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if (i2c_bit_count == 9 || i2c_mode == I2C_READ) {
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if (i2c_bit_count == 9) {
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// when a full byte is received, respond with ACK
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i2c_sda_read = 0; // ACK
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i2c_bit_count = 0;
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}
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switch (i2c_mode) {
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case I2C_DEVICEID: {
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if (device_debug)
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bprintf(0, _T("deviceid: %x\n"), i2c_shifter);
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if (i2c_device == I2C_X24C01) { // special handling for X24c01!
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i2c_address = (i2c_shifter & 0xfe) >> 1;
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if (device_debug)
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bprintf(0, _T("x24c01 address: %x\n"), i2c_address);
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i2c_mode = (i2c_shifter & 1) ? I2C_READ : I2C_WRITE;
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} else
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if ((i2c_shifter & 0xf0) == 0xa0) {
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i2c_selected_device = i2c_shifter;
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i2c_mode = (i2c_shifter & 1) ? I2C_READ : I2C_ADDR;
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} else {
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// not our device on the i2c bus, try again
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i2c_mode = I2C_DEVICEID;
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}
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}
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break;
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case I2C_ADDR: {
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i2c_address = i2c_shifter;
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if (i2c_devices[i2c_device].size >= 0x1000) {
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i2c_mode = I2C_ADDR_EXT;
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} else {
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i2c_address |= (i2c_selected_device & 0xe) << 7;
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i2c_mode = I2C_WRITE;
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}
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}
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break;
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case I2C_ADDR_EXT: {
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i2c_address = (i2c_address << 8) | i2c_shifter;
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i2c_mode = I2C_WRITE;
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}
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break;
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case I2C_WRITE: {
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i2c_memory[i2c_address & i2c_mask] = i2c_shifter;
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i2c_address = ((i2c_address + 1) & i2c_page_mask) | (i2c_address & ~i2c_page_mask);
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}
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break;
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case I2C_READ: {
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if (i2c_bit_count == 0) {
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i2c_shifter = i2c_memory[i2c_address & i2c_mask];
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i2c_address++;
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}
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i2c_sda_read = (i2c_shifter >> 7) & 1;
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i2c_shifter = i2c_shifter << 1;
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i2c_bit_count++;
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if (i2c_bit_count == 9) {
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// after the last bit is read, respond with ACK
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i2c_sda_read = 0;
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i2c_bit_count = 0;
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}
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}
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break;
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}
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}
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}
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i2c_sda = sda;
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i2c_scl = scl;
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}
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@ -0,0 +1,27 @@
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enum {
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I2C_NONE = 0,
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I2C_24C01,
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I2C_X24C01,
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I2C_X24C02,
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I2C_24C02,
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I2C_24C04,
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I2C_24C08,
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I2C_24C16,
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I2C_24C32,
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I2C_24C64,
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I2C_24C128,
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I2C_24C256
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};
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void i2c_init(UINT8 device, UINT8 sda, UINT8 scl, UINT8 sda_read);
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void i2c_init(UINT8 device);
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void i2c_exit();
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void i2c_scan(INT32 nAction, INT32 *pnMin);
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void i2c_reset();
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bool i2c_read();
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void i2c_write_bit(bool sda, bool scl);
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UINT32 i2c_read_bus8(UINT32 address);
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UINT32 i2c_read_bus16(UINT32 address);
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void i2c_write_bus8(UINT32 address, UINT8 data);
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void i2c_write_bus16(UINT32 data);
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