AT83EC5123 ATMEL Corporation, AT83EC5123 Datasheet - Page 108

• Manufacturer Part Number: AT83EC5123
• Description: (AT8xx512x) Smart Card Reader ICs
• Manufacturer: ATMEL Corporation

Serial Peripheral DATa Register
(SPDAT)
10
AT8xC5122/23
The Serial Peripheral Data Register (Table 81) is a read/write buffer for the receive data
register. A write to SPDAT places data directly into the shift register. No transmit buffer
is available in this model.
A read of the SPDAT returns the value located in the receive buffer and not the content
of the shift register.
Table 81. Serial Peripheral Data Register - SPDAT (C5h)
Reset Value = XXXX XXXXb
Bit Number
7-0
R7
7
Mnemonic Description
R7:0
Bit
R6
6
Receive data bits
SPCON, SPSTA and SPDAT registers may be read and written at any time while
there is no on-going exchange. However, special care should be taken when
writing to them while a transmission is on-going:
Do not change SPR2, SPR1 and SPR0
Do not change CPHA and CPOL
Do not change MSTR
Clearing SPEN would immediately disable the peripheral
Writing to the SPDAT will cause an overflow
R5
5
R4
4
R3
3
R2
2
R1
1
4202B–SCR–07/03
R0
0