diff options
Diffstat (limited to 'romdb.c')
| -rw-r--r-- | romdb.c | 141 |
1 files changed, 134 insertions, 7 deletions
@@ -16,19 +16,55 @@ #define RAM_END 0x1B8 #define REGION_START 0x1F0 -void eeprom_init(eeprom_state *state) +enum { + I2C_IDLE, + I2C_START, + I2C_DEVICE_ACK, + I2C_ADDRESS_HI, + I2C_ADDRESS_HI_ACK, + I2C_ADDRESS, + I2C_ADDRESS_ACK, + I2C_READ, + I2C_READ_ACK, + I2C_WRITE, + I2C_WRITE_ACK +}; + +char * i2c_states[] = { + "idle", + "start", + "device ack", + "address hi", + "address hi ack", + "address", + "address ack", + "read", + "read_ack", + "write", + "write_ack" +}; + +void eeprom_init(eeprom_state *state, uint8_t *buffer, uint32_t size) { state->slave_sda = 1; state->host_sda = state->scl = 0; + state->buffer = buffer; + state->size = size; + state->state = I2C_IDLE; } void set_host_sda(eeprom_state *state, uint8_t val) { if (state->scl) { if (val & ~state->host_sda) { - //stop condition + //low to high, stop condition + state->state = I2C_IDLE; + state->slave_sda = 1; } else if (~val & state->host_sda) { - //start condition + //high to low, start condition + state->state = I2C_START; + state->slave_sda = 1; + state->counter = 8; } } state->host_sda = val; @@ -37,7 +73,98 @@ void set_host_sda(eeprom_state *state, uint8_t val) void set_scl(eeprom_state *state, uint8_t val) { if (val & ~state->scl) { - //latch sda + //low to high transition + switch (state->state) + { + case I2C_START: + case I2C_ADDRESS_HI: + case I2C_ADDRESS: + case I2C_WRITE: + state->latch = state->host_sda << 7 | state->latch >> 1; + state->counter--; + if (!state->counter) { + switch (state->state & 0x7F) + { + case I2C_START: + state->state = I2C_DEVICE_ACK; + break; + case I2C_ADDRESS_HI: + state->address = state->latch << 8; + state->state = I2C_ADDRESS_HI_ACK; + break; + case I2C_ADDRESS: + state->address |= state->latch; + state->state = I2C_ADDRESS_ACK; + break; + case I2C_WRITE: + state->buffer[state->address] = state->latch; + state->state = I2C_WRITE_ACK; + state->address++; + //TODO: page mask + state->address &= state->size-1; + break; + } + } + break; + case I2C_DEVICE_ACK: + if (state->latch & 1) { + state->state = I2C_READ; + state->counter = 8; + state->latch = state->buffer[state->address]; + state->address++; + //TODO: page mask + state->address &= state->size-1; + } else { + if (state->size < 256) { + state->address = state->latch >> 1; + state->state = I2C_WRITE; + } else if (state->size < 8192) { + state->address = state->latch << 8; + state->state = I2C_ADDRESS; + } else { + state->state = I2C_ADDRESS_HI; + } + state->counter = 8; + } + break; + case I2C_ADDRESS_HI_ACK: + state->state = I2C_ADDRESS; + break; + case I2C_ADDRESS_ACK: + state->state = I2C_WRITE; + break; + case I2C_READ: + state->counter--; + if (!state->counter) { + state->state = I2C_READ_ACK; + } + break; + case I2C_READ_ACK: + state->state = I2C_READ; + break; + case I2C_WRITE_ACK: + state->state = I2C_WRITE; + break; + } + } else if (~val & state->scl) { + //high to low transition + switch (state->state & 0x7F) + { + case I2C_DEVICE_ACK: + case I2C_ADDRESS_HI_ACK: + case I2C_ADDRESS_ACK: + case I2C_READ_ACK: + case I2C_WRITE_ACK: + state->slave_sda = 0; + break; + case I2C_READ: + state->slave_sda = state->latch >> 7; + state->latch = state->latch << 1; + break; + default: + state->slave_sda = 1; + break; + } } state->scl = val; } @@ -192,8 +319,8 @@ void * write_eeprom_i2c_w(uint32_t address, void * context, uint16_t value) set_host_sda(&gen->eeprom, (value & map->sda_write_mask) != 0); } if (map->scl_mask) { - printf("scl: %d\n", (value & map->scl_mask) != 0); - set_scl(&gen->eeprom, (value & map->sda_write_mask) != 0); + set_scl(&gen->eeprom, (value & map->scl_mask) != 0); + printf("scl: %d, state: %s, counter: %d\n", (value & map->scl_mask) != 0, i2c_states[gen->eeprom.state], gen->eeprom.counter); } return context; } @@ -221,7 +348,7 @@ void * write_eeprom_i2c_b(uint32_t address, void * context, uint8_t value) set_host_sda(&gen->eeprom, (expanded & map->sda_write_mask) != 0); } if (map->scl_mask & mask) { - printf("scl: %d\n", (expanded & map->scl_mask) != 0); + printf("scl: %d, state: %s\n", (expanded & map->scl_mask) != 0, i2c_states[gen->eeprom.state]); set_scl(&gen->eeprom, (expanded & map->scl_mask) != 0); } return context; |