Posted on November 24, 2014 at 21:06Hi,
I am using the STM32F2xx cube API to implement a raw bitbang usb driver for the FTDI ft245. I am currently achieving speed of 5000 bytes/s. I would like to improve the speed. The bitbang code is simple as:
<..>
__disable_irq();
// set data pins
HAL_GPIO_WritePin(FT_D0_PORT, FT_D0_PIN, (CHECK_BIT(data, 0) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D1_PORT, FT_D1_PIN, (CHECK_BIT(data, 1) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D2_PORT, FT_D2_PIN, (CHECK_BIT(data, 2) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D3_PORT, FT_D3_PIN, (CHECK_BIT(data, 3) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D4_PORT, FT_D4_PIN, (CHECK_BIT(data, 4) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D5_PORT, FT_D5_PIN, (CHECK_BIT(data, 5) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D6_PORT, FT_D6_PIN, (CHECK_BIT(data, 6) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
HAL_GPIO_WritePin(FT_D7_PORT, FT_D7_PIN, (CHECK_BIT(data, 7) == 0) ? GPIO_PIN_RESET : GPIO_PIN_SET);
__enable_irq();
<...>
The pins are configured as follow:
FT_DX_PORT, FT_DX_PIN, GPIO_MODE_INPUT, GPIO_NOPULL, GPIO_SPEED_HIGH
is there anything I can do or example I could follow or inspire myself? (beside implementing some asm?)
thanx
Mart
#bitband-bit-bang
