C511_1 Datasheet, PDF (86/128 Pages) Siemens Semiconductor Group – 8-Bit CMOS Microcontroller

On-Chip Peripheral Units
6.4.8.4 Data Registers STB and SRB
The register STB holds the data to be transmitted while SRB contains the data which was received
during the last transfer. A write to the STB places the data directly into the shift register for
transmission. Only in master mode this also will initiate the transmission/reception process. When
a write collision occurs STB will hold the value written erroneously. This value can be read by
reading from STB.
A read from the receive buffer register SRB will transfer the data of the last transfer completed. This
register must be read before the next transmission completes or the data will be lost. There is no
indication for this overrun condition.
After reset the contents of the shift register and the receive buffer register are undefined.
6.4.8.5 Mode Test Register SSCMOD
The register SSCMOD is used to enable test modes during factory test. It must not be written or
modified during normal operation of the SAB-C511/513.
Special Function Registers SSCMOD (Address EBH)
MSB
Bit No. 7
6
5
4
3
2
EBH
0
0
0
0
0
0
Reset Value : 00H
LSB
1
0
0
0
SSCMOD
Bit
Function
7-0
All bits of this register are set to 0 after reset and must not be
modified !
Semiconductor Group
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