DLPS117B July 2018 – October 2020 DLPC6421
The DLPC6421 controller provides an external program memory chip select:
The DLPC6421 controller provides enough Program Memory Address pins to support a flash device up to 128 Mb. The two most significant address bits (i.e. PM_ADDR_22 and PM_ADDR_21) are shared on pins GPIO_36 and GPIO_35 respectively. Like other GPIO pins, these pins float in a high-impedance input state following reset; therefore, if these GPIO pins are to be reconfigured as Program Memory Address pins, they require board-level pull-down resistors to prevent any flash address bits from floating until software is able to reconfigure the pins from GPIO to Program Memory Address. Also note that until software reconfigures the pins from GPIO to Program Memory Address, upper portions of flash memory are not accessible.
Table 7-2 shows typical GPIO_35 and GPIO36 pin configuration for various flash sizes.
|FLASH SIZE||GPIO_36 Pin Configuration||GPIO_35 Pin Configuration|
|32 Mb or less||PM_ADDR_22(1)||PM_ADDR_21(1)|