Intel NETWORK PROCESSOR IXP2800 - Manual (Page 148)

148 Hardware Reference Manual
Intel
®
IXP2800 Network Processor
Intel XScale ® Core
3.12.7.6.2 Mode 0 Single Write Transfer for Self-Timing Device
Figure 39 depicts the single write transfer for a self-timing device with the CSR programmed to
setup=4, pulse width=0, and hold=3. Similarly, a read transaction is attached behind.
Similar to the single write for fixed-timed device, the ALE_L, CS_L[1:0], AD[7:0], and A[1:0]
follow the same pattern, and the timing is controlled by the timing control register — except for the
WR_L, which is terminated depending on the SP_ACK_L returned from the self-timing device.
The time-out counter will be set to 255. If no SP_ACK_L responds back when the time-out counter
reaches 0, the transaction is terminated with a time-out. An interrupt signal is issued to the bus
master simultaneously with the time-out register update.
Figure 39. Mode 0 Single Write Transfer for a Self-Timing Device
A9707-03
SP_CLK
SP_ALE_L
SP_CS_L
[1:0]
SP_WR_L
D[7:0]
A[1:0]
24:18 17:10 9:2 24:18 17:10 9:2
SP_RD_L
SP_A[1:0]
SP_AD[7:0]
SP_ACK_L
2 0 4 6 8 10 12 14 16 18 20