MicroWire Interface
7-33
MPU Public Peripherals
Table 7–29. Control and Status Register (CSR) (Continued)
Bit
Reset
Value
Function
Value
Name
11–10
INDEX
Index of the external device
Undefined
00
CS0
01
Reserved
10
Reserved
11
CS3
9–5
NB_BITS_WR
Number of bits to transmit
Undefined
4–0
NB_BITS_RD
Number of bits to receive
Undefined
This register sets up the serial interface for the first and the second external
components.
Table 7–30. Setup Register 1 (SR1)
Bit
Name
Value
Function
Reset
Value
11–6
Reserved
5
CS0_CHK
Before activating a write process, checks if external
device is ready.
Undefined
0
No check is done and the write process is immediately
executed.
1
If DI signal is low, the interface considers the external
component busy; if DI is high, the interface considers
that the first external component is ready and starts the
write process.
Used when CS0 is selected.