Information

Enhanced Secure Digital Host Controller
MPC8308 PowerQUICC II Pro Processor Reference Manual, Rev. 1
11-34 Freescale Semiconductor
Table 11-21 describes the relationship between command CRC error and command timeout error for Auto
CMD12.
There are three scenarios when AUTOC12ERR can be changed:
• When eSDHC is going to issue Auto CMD12
— Set AC12NE if Auto CMD12 cannot be issued due to an error in the previous command.
— Clear AC12NE if Auto CMD12 is issued.
• At the end bit of an Auto CMD12 response
— Check received responses by checking the error bits 30–27.
— Set if error is detected.
— Clear if error is not detected.
• Before reading AUTOC12ERR[CNIBAC12E]
— Set CNIBAC12E if there is a command that cannot be issued
— Clear CNIBAC12E if there is no command to issue
The timing of generating the Auto CMD12 error and writing to the command register is asynchronous. The
command may be blocked by any Auto CMD12 error causing CNIBAC12E to be set. Therefore, it is
suggested to read this register only when IRQSTAT[AC12E] is set. An Auto CMD12 error interrupt is
generated when one of the error bits 31–27 is set to 1. The CNIBAC12E error bit does not generate an
interrupt.
30 AC12TOE Auto CMD12 timeout error. Occurs if no response is returned within 64 SD_CLK cycles
from the end bit of the command. If this bit is set, the other error status bits (29–27) are
meaningless.
0 No error
1 Time out
31 AC12NE Auto CMD12 not executed. If a memory multiple block data transfer is not started due to
command error, this bit is not set because it is not necessary to issue Auto CMD12.
Setting this bit means eSDHC cannot issue Auto CMD12 to stop the memory multiple
block data transfer due to some error. If this bit is set, the other error status bits (30–27)
are meaningless.
0 Executed
1 Not executed
Table 11-21. Relationship Between Command CRC Error and Command Timeout Error
for Auto CMD12
Auto CMD12 CRC Error Auto CMD12 Timeout Error Types of Error
00No error
0 1 Response timeout error
1 0 Response CRC error
1 1 SD_CMD line conflict
Table 11-20. AUTOC12ERR Field Descriptions (continued)
Bit Name Description