If I want to initiate DMA transfers using an external pin of the processor, which pins can I use? I found that there are 4 possible signals that can be used for this per reference manual pg. 3-15: IRQ[0], IRQ[1], IRQ[2], IRQ[3]. I found that these interrupts may be utilized on multiple uC pins as seen below. Am I able to use any of the pins below or only specific ones? How can I tell?
F25 | ETPUC9_IRQ0_GPIO450 | 0 |
AF17 | EMIOS14_IRQ0_GPIO193 | 0 |
F26 | ETPUC10_IRQ1_GPIO451 | 1 |
AE16 | EMIOS15_IRQ1_GPIO194 | 1 |
L4 | BOOTCFG0_IRQ2_GPIO211 | 2 |
G22 | ETPUC11_IRQ2_GPIO452 | 2 |
L3 | BOOTCFG1_IRQ3_GPIO212 | 3 |
G23 | ETPUC12_IRQ3_GPIO453 | 3 |
G24 | ETPUC13_IRQ4_GPIO454 | 4 |
M3 | PLLCFG0_IRQ4_GPIO208 | 4 |
Hi,
Yes, you can use IRQ0-IRQ3 to start DMA transfers as you wrote.
You can select any pin by configuring alternate function of respective PCR register. For example to use IRQ0 on AF17 pad just configure
Moreover you have to enable the edge detector in SIU_IREER or SIU_IFEER registers for an particular IRQ and enable DMA request in SIU_DIRSR.
The SIU_EIISR gives you a possibility to select the source for the external interrupt/DMA inputs. By default the IRQn sources are selected.
BR, Petr