Intel® PXA255 Processor Developer’s Manual 15-25

MultiMediaCard Controller
This is a read/wri te register. Ignore reads from reserved bit s. Write zeros to res erved bits.
15.5.4 MMC_SPI Register (MMC_SPI)

MMC_SPI, shown in Table 15-8, is for SPI mode only and is set by the software.

This is a read/wri te register. Ignore reads from reserved bit s. Write zeros to res erved bits.

Table 15-7. MMC_CLK Bit Definitions

Physical Address
0x4110_0008 MMC_CLKRT Register MultiMediaCard Controller
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
reserved CLK_RAT
E[2:0]
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits Name Description
31:3 — reserved
2:0 CLK_RATE[2:
0]
000 – 20MHz clock
001 – 10MHz clock, 1/2 of 20 MHz clock
010 – 5MHz clock, 1/4 of 20 MHz clock
011 – 2.5MHz clock, 1/8 of 20MHz clock
100 – 1.25MHz clock, 1/16 of 20MHz clock
101 – 0.625MHz clock, 1/32 of 20 MHz clock
110 – 0.3125MHz clock, 1/64 of 20 MHz clock
111 – res erve d

Table 15-8. MMC_SPI Bit Definitions (Sheet 1 of 2)

Physical Address
0x4110_000c MMC_SPI Register MultiMediaCard Controller
Bit 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
reserved
SPI_CS_ADDRESS
SPI_CS_EN
CRC_ON
SPI_EN
Reset 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
Bits Name Description
31:4 — reserved
3SPI_CS_ADD
RESS
Specifies the relative address of the card to activate the SPI CS
0 – Enables CS1
1 – Enables CS0
2 SPI_CS_EN SPI Chip Select Enable
0 – Disables the SPI chip select
1 – Enables the SPI chip select
1CRC_ON
CRC Generation Enable
0 – Disables CRC generation and verification
1 – Enables CRC generation and verification