diff options
Diffstat (limited to 'ports/stm32/sdram.c')
| -rw-r--r-- | ports/stm32/sdram.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/ports/stm32/sdram.c b/ports/stm32/sdram.c index e99f34d22..7104eb68e 100644 --- a/ports/stm32/sdram.c +++ b/ports/stm32/sdram.c @@ -245,15 +245,15 @@ static void sdram_init_seq(SDRAM_HandleTypeDef /* Send the command */ HAL_SDRAM_SendCommand(hsdram, command, 0x1000); - /* Step 8: Set the refresh rate counter + /* Step 8: Set the refresh rate counter. + Assuming 90MHz frequency, 8192 refresh cycles and 64ms refresh rate: RefreshRate = 64 ms / 8192 cyc = 7.8125 us/cyc - RefreshCycles = 7.8125 us * 90 MHz = 703 According to the formula on p.1665 of the reference manual, we also need to subtract 20 from the value, so the target refresh rate is 703 - 20 = 683. */ - #define REFRESH_COUNT (MICROPY_HW_SDRAM_REFRESH_RATE * 90000 / 8192 - 20) + #define REFRESH_COUNT (MICROPY_HW_SDRAM_REFRESH_RATE * MICROPY_HW_SDRAM_FREQUENCY_KHZ / MICROPY_HW_SDRAM_REFRESH_CYCLES - 20) HAL_SDRAM_ProgramRefreshRate(hsdram, REFRESH_COUNT); #if defined(STM32F7) || defined(STM32H7) |