diff options
| -rw-r--r-- | docs/eeprom_driver.md | 3 | ||||
| -rw-r--r-- | drivers/eeprom/eeprom_i2c.c | 23 |
2 files changed, 25 insertions, 1 deletions
diff --git a/docs/eeprom_driver.md b/docs/eeprom_driver.md index e2c262546d..6dcf10c04d 100644 --- a/docs/eeprom_driver.md +++ b/docs/eeprom_driver.md @@ -31,6 +31,9 @@ Currently QMK supports 24xx-series chips over I2C. As such, requires a working i `#define EXTERNAL_EEPROM_PAGE_SIZE` | Page size of the EEPROM in bytes, as specified in the datasheet | 32 `#define EXTERNAL_EEPROM_ADDRESS_SIZE` | The number of bytes to transmit for the memory location within the EEPROM | 2 `#define EXTERNAL_EEPROM_WRITE_TIME` | Write cycle time of the EEPROM, as specified in the datasheet | 5 +`#define EXTERNAL_EEPROM_WP_PIN` | If defined the WP pin will be toggled appropriately when writing to the EEPROM. | _none_ + +Some I2C EEPROM manufacturers explicitly recommend against hardcoding the WP pin to ground. This is in order to protect the eeprom memory content during power-up/power-down/brown-out conditions at low voltage where the eeprom is still operational, but the i2c master output might be unpredictable. If a WP pin is configured, then having an external pull-up on the WP pin is recommended. Default values and extended descriptions can be found in `drivers/eeprom/eeprom_i2c.h`. diff --git a/drivers/eeprom/eeprom_i2c.c b/drivers/eeprom/eeprom_i2c.c index 4210f06f9f..8e80ff544f 100644 --- a/drivers/eeprom/eeprom_i2c.c +++ b/drivers/eeprom/eeprom_i2c.c @@ -16,6 +16,9 @@ #include <stdint.h> #include <string.h> +#if defined(EXTERNAL_EEPROM_WP_PIN) +# include "gpio.h" +#endif /* Note that the implementations of eeprom_XXXX_YYYY on AVR are normally @@ -50,7 +53,14 @@ static inline void fill_target_address(uint8_t *buffer, const void *addr) { } } -void eeprom_driver_init(void) { i2c_init(); } +void eeprom_driver_init(void) { + i2c_init(); +#if defined(EXTERNAL_EEPROM_WP_PIN) + /* We are setting the WP pin to high in a way that requires at least two bit-flips to change back to 0 */ + writePin(EXTERNAL_EEPROM_WP_PIN, 1); + setPinInputHigh(EXTERNAL_EEPROM_WP_PIN); +#endif +} void eeprom_driver_erase(void) { #if defined(CONSOLE_ENABLE) && defined(DEBUG_EEPROM_OUTPUT) @@ -89,6 +99,11 @@ void eeprom_write_block(const void *buf, void *addr, size_t len) { uint8_t * read_buf = (uint8_t *)buf; uintptr_t target_addr = (uintptr_t)addr; +#if defined(EXTERNAL_EEPROM_WP_PIN) + setPinOutput(EXTERNAL_EEPROM_WP_PIN); + writePin(EXTERNAL_EEPROM_WP_PIN, 0); +#endif + while (len > 0) { uintptr_t page_offset = target_addr % EXTERNAL_EEPROM_PAGE_SIZE; int write_length = EXTERNAL_EEPROM_PAGE_SIZE - page_offset; @@ -116,4 +131,10 @@ void eeprom_write_block(const void *buf, void *addr, size_t len) { target_addr += write_length; len -= write_length; } + +#if defined(EXTERNAL_EEPROM_WP_PIN) + /* We are setting the WP pin to high in a way that requires at least two bit-flips to change back to 0 */ + writePin(EXTERNAL_EEPROM_WP_PIN, 1); + setPinInputHigh(EXTERNAL_EEPROM_WP_PIN); +#endif } |