diff options
| -rw-r--r-- | firmware/target/arm/rk27xx/i2c-rk27xx.c | 15 |
1 files changed, 8 insertions, 7 deletions
diff --git a/firmware/target/arm/rk27xx/i2c-rk27xx.c b/firmware/target/arm/rk27xx/i2c-rk27xx.c index 093fe70..f9f2093 100644 --- a/firmware/target/arm/rk27xx/i2c-rk27xx.c +++ b/firmware/target/arm/rk27xx/i2c-rk27xx.c @@ -131,13 +131,14 @@ void i2c_init(void) /* set I2C divider to stay within allowed SCL freq limit * APBfreq = 50Mhz - * SCLfreq = (APBfreq/5*(I2CCDVR[5:3] + 1) * 2^((I2CCDVR[2:0] + 1)) - */ - - /* we are driving this slightly above specs - * (6<<3) | (1<<0) 416kHz - * (7<<3) | (1<<0) 357kHz - * (6<<3) | (2<<0) 208kHz + * I2C_div = (I2CCDVR[5:3] + 1) * 2^((I2CCDVR[2:0] + 1)) + * SCLfreq = APBfreq/(5*I2C_div) + * + * (5<<3) | (1<<0) 416.7 KHz (above spec) + * (6<<3) | (1<<0) 357.1 kHz + * (7<<3) | (1<<0) 312.4 kHz + * (6<<3) | (2<<0) 178.6 kHz + * (7<<3) | (2<<0) 156.3 kHz */ I2C_OPR = (I2C_OPR & ~(0x3F)) | (6<<3) | (1<<0); |