UM10208_2
© NXP B.V. 2007. All rights reserved.
User manual
Rev. 02 — 1 June 2007
297 of 362
NXP Semiconductors
UM10208
Chapter 23: LPC2800 SD/MMC
Note: After a data write, data cannot be written to this register for three MCLK clock
periods plus two PCLK clock periods.
5.4 Argument Register (MCIArgument - 0x8010 0008)
The MCIArgument register contains a 32 bit command argument, which is sent to a card
as part of a command message.
shows the MCIArgument register.
If a command contains an argument, it must be loaded into the argument register before
writing a command to the command register.
5.5 Command Register (MCICommand - 0x8010 000C)
The MCICommand register contains the command index and command type bits:
•
The command index is sent to a card as part of a command message.
•
The command type bits control the Command Path State Machine (CPSM). Writing 1
to the enable bit starts the command send operation, while clearing the bit disables
the CPSM.
shows the MCICommand register.
Note: After a data write, data cannot be written to this register for three MCLK clock
periods plus two PCLK clock periods.
Table 334. Argument register (MCIArgument - 0x8010 0008)
Bit
Symbol
Description
Reset Value
31:0
CmdArg
Command argument
0x0000 0000
Table 335. Command register (MCICommand - 0x8010 000C)
Bit
Symbol
Description
Reset
Value
5:0
CmdIndex
Command index.
0
6
Response
If set, CPSM waits for a response.
0
7
LongRsp
If set, CPSM receives a 136 bit long response.
0
8
Interrupt
If set, CPSM disables the command timer and waits for an
interrupt request from a card.
0
9
W8PEND
If set, CPSM waits for CmdPend before it starts sending a
command.
0
10
CPSM_EN
If set, CPSM is enabled.
0
31:11
-
Reserved, user software should not write ones to reserved bits.
The value read from a reserved bit is not defined.
-
Table 336. Command Response Types
Response
Long Response
Description
0
0
No response, expect CmdSent flag.
0
1
No response, expect CmdSent flag.
1
0
Short response, expect CmdRespEnd or CmdCrcFail flag.
1
1
Long response, expect CmdRespEnd or CmdCrcFail flag.