MEC1404 Datasheet, PDF (140/572 Pages) Microchip Technology – Keyboard and Embedded Controller Products for Notebook PC

MEC140X/1X
6.11.2 QMSPI CONTROL REGISTER
Offset ^04h
Bits
Description
Type
31:16 TRANSFER_LENGTH
R/W
The length of the SPI transfer. The count is in bytes or bits,
depending on the value of TRANSFER_LENGTH_BITS. A value of
‘0’ means an infinite length transfer.
15:12 DESCRIPTION_BUFFER_POINTER
R/W
This field selects the first buffer used if Description Buffers are
enabled.
11 DESCRIPTION_BUFFER_ENABLE
R/W
This enables the Description Buffers to be used.
1=Description Buffers in use. The first buffer is defined in DESCRIP-
TION_BUFFER_POINTER
0=Description Buffers disabled
10 TRANSFER_LENGTH_BITS
R/W
1=TRANSFER_LENGTH defined in bits
0=TRANSFER_LENGTH defined in bytes
9 CLOSE_TRANSFER_ENABLE
R/W
This selects what action is taken at the end of a transfer. When the
transaction closes, the Chip Select de-asserts, the SPI interface
returns to IDLE and the DMA interface terminates When Descrip-
tion Buffers are in use this bit must be set only on the Last Buffer.
1=The transaction is terminated
0=The transaction is not terminated
8:7 RX_DMA_ENABLE
R/W
This bit enables DMA support for Receive Transfer. If enabled,
DMA will be requested to empty the FIFO until either the interface
reaches TRANSFER_LENGTH or the DMA sends a termination
request. The size defined here must match DMA programmed
access size.
1=DMA is enabled.and set to 1 Byte
2=DMA is enabled and set to 2 Bytes
3=DMA is enabled and set to 4 Bytes
0=DMA is disabled. All data in the Receive Buffer must be emptied
by firmware
6 RX_TRANSFER_ENABLE
R/W
This bit enables the receive function of the SPI interface.
1=Receive is enabled. Data received from the SPI Slave is stored
in the Receive Buffer
0=Receive is disabled
Default
0h
Reset
Event
RESET
0h
RESET
0h
RESET
0h
RESET
1h
RESET
0h
RESET
0h
RESET
DS00001956D-page 140
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