AT89C5122 ATMEL [ATMEL Corporation], AT89C5122 Datasheet - Page 84

• Manufacturer Part Number: AT89C5122
• Description: MICROCONTROLLER WITH USB AND SMART CARD READER INTERFACES
• Manufacturer: ATMEL [ATMEL Corporation]

Table 49. Smart Card Selection Register - SCSR (S:ABh)
Reset Value = X000 1000b
Table 50. Smart Card Transmit / Receive Buffer - SCIBUF (S:AA)
Reset Value = 0000 0000b
84
Bit Number
Bit Number
3-2
7
7
-
7
6
5
4
1
0
-
-
AT8xC5122/23
Bit Mnemonic
Bit Mnemonic
ALTKPS1:0
CREPSEL
BGTEN
SCCLK1
BGTEN
SCRS
6
6
-
-
-
-
Description
Smart Card Transmit / Receive Buffer
- A new byte can be written in the buffer to be transmitted on the I/O pin when SCTBE bit is set.
The bits are sorted and copied on the I/O pin versus the active convention.
- A new byte received from I/O pin is ready to be read when SCRI bit is set.
The bits are sorted versus the active convention.
Description
Reserved
The value read from this bit is indeterminate. Do not change this bit.
Block Guard Time Enable
Set this bit to select the minimum interval between the leading edge of the start bits of the last character
received from the ICC and the first character sent by the Terminal. The transfer of GT[8-0] value to the BGT
counter is done on the rising edge of the BGTEN.
Clear this bit to suppress the minimum time between reception and transmission.
Reserved
The value read from this bit is indeterminate. Do not change this bit.
Character repetition selection
Clear this bit to select 5 times transmission (1 original + 4 repetitions) before parity error indication (conform to
EMV)
Set this bit to select 4 times transmission (1 original + 3 repetitions) before parity error indication
Alternate Card Clock prescaler factor
01 ALTKPS = 1: prescaler factor equals 2
10 ALTKPS = 2: prescaler factor equals 4 (reset value)
11 ALTKPS = 3: prescaler factor equals 8
Alternate card clock selection
Set to select the prescaled PR3 clock for CCLK1 (P1.7) pin
Clear to select P1.7 port bit
Smart Card Register Selection
The SCRS bit selects which set of the SCIB registers is accessed.
00 ALTKPS = 0: prescaler factor equals 1
5
5
-
-
CREPSEL
4
4
-
ALTKPS1
3
3
-
ALTKPS0
2
2
-
SCCLK1
1
1
-
4202D–SCR–06/05
SCRS
0
0
-