Master Read Using Polled Method

Zynq UltraScale+ Device Technical Reference Manual (UG1085)

Document ID
Release Date
2.4 English

1.Set the transfer direction as read and clear the FIFOs. Write 41h to the Control register.

2.Clear the interrupts. Read and write back the read value of the IRS status register.

3.Write the read data count to the transfer size register and hold bus, if required. Write the read data count value to the Transfer_Size register. If the read data count is greater than the FIFO depth, set Control [HOLD] = 1.

4.Write the slave address. Write the address to the Address register.

5.Wait for data to be received into the FIFO. Poll on Status [RXDV] = 1.

a.If Status [RXDV] = 0, and any of the following interrupts are set: Interrupt_Status [NACK], Interrupt_Status [ARB_LOST], Interrupt_Status [RX_OVF], or Interrupt_Status [RX_UNF], then stop the transfer and report the error, otherwise continue to poll on the Status [RXDV].

b.If Status [RXDV] = 1, and if any of the following interrupts are set: Interrupt_Status [NACK], Interrupt_Status [ARB_LOST], Interrupt_Status [RX_OVF], or Interrupt_Status [RX_UNF], then stop the transfer and report the error. Otherwise, go to step 6.

6.Read the data and update the count. Read the data from the FIFO until Status [RXDV] = 1. Decrement the read data count and if it is less than or equal to the FIFO depth, clear the Control [HOLD] register.

7.Check for the completion of transfer. If the total read count reaches zero, poll on Interrupt_Status [COMP] = 1. Otherwise, continue from step 5.