Intel PXA26X - Manual (Page 332)

8-14 Intel® PXA26x Processor Family Developer’s Manual
Synchronous Serial Port Controller
8.7.2.6 Microwire Transmit Data Size (MWDS)
Use the Microwire transmit data size (MWDS) bit to select the 8- or 16-bit size for command word
transmissions in the National Microwire frame format. When MWDS=0, 8-bit command words are
transmitted. When MWDS=1, 16-bit command words are transmitted. The MWDS setting is
ignored for all other frame formats.
8.7.2.7 Transmit FIFO Interrupt/DMA Threshold (TFT)
This 4-bit value sets the level at or below which the FIFO controller triggers a DMA service
request and, if enabled, an interrupt request. Refer to
Table 8-4 for suggested TFT values associated
with DMA servicing.
Figure 8-4. Motorola SPI* Frame Formats for SPO and SPH Programming
SSPSCLK SPO=0
...
SSPSCLK SPO=1
...
SSPSFRM
...
SSPTXD Bit<N> Bit<N-1 > ... Bit<1> Bit<0>
SSPRXD Bit<N>
Bit<N-
1>
... Bit<1> Bit<0>
MSB 4 to 16 Bits LSB
SPH = 0
SSPSCLK SPO=0
...
SSPSCLK SPO=1
...
SSPSFRM
...
SSPTXD Bit<N>
Bit<N-
1>
... Bit<1> Bit<0>
SSPRXD Bit<N>
Bit<N-
1>
... Bit<1> Bit<0>
MSB 4 to 16 Bits LSB
SPH = 1