Write Operation by the Master
2-6
2.4
Write Operation by the Master
The process for the write operation by the master is the same in 4-bit and 8-bit
modes. The write operation by the master happens when the slave is ready
to request data or command from the master. The slave initiates the write pro-
cess by pulling INRDY low when the slave is ready to receive data.
The following events take place during the write operation:
1) The MSP53C691 sets INRDY low to indicate that it is ready to receive data
from the microcontroller.
2) The microcontroller sets R/W low to indicate a write operation.
3) The microcontroller puts the data in the external data-bus.
4) The microcontroller sets STROBE low after the data is valid.
5) The microcontroller sets STROBE high after a minimum of 300 ns. The
MSP53C691 also pulls INRDY high at the rising edge of STROBE.
6) The data is latched in the MSP53C691 at the rising edge of STROBE.
When the microcontroller sets STROBE high, the MSP53C691 sets INRDY
high to indicate that the MSP53C691 is not ready to receive any more data.
Figure 2–4. Data Transfer—Write
R/W
a) Sequence of events for a single write operation
b) Write—Two speech data transfer sequences
INRDY
DATA
COMMAND/DATA
INRDY
DATA
COMMAND/DATA
R/W
STROBE
STROBE
Summary of Contents for MSP53C691
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