DS_1209F_004
73S1209F Data Sheet
Rev. 1.2
95
FD Control Register (FDReg): 0xFE13
Å
0x11
Table 91: The FDReg Register
MSB
LSB
FVAL.3 FVAL.2 FVAL.1 FVAL.0 DVAL.3 DVAL.2 DVAL.1 DVAL.0
Bit Symbol
Function
FDReg.7 FVAL.3
Refer to Table 93 above. This value is converted per the table to set the
divide ratio used to generate the baud rate (ETU). Default, also used for
ATR, is 0001 (Fi = 372). This value is used by the selected interface.
FDReg.6 FVAL.2
FDReg.5 FVAL.1
FDReg.4 FVAL.0
FDReg.3 DVAL.3
Refer to Table 93 above. This value is used to set the divide ratio used to
generate the smart card CLK. Default, also used for ATR, is 0001 (Di = 1).
FDReg.2 DVAL.2
FDReg.1 DVAL.1
FDReg.0 DVAL.0
This register uses the transmission factors F and D to set the ETU (baud) rate. The values in this register
are mapped to the ISO 7816 conversion factors as described below. The CLK signal for each interface is
created by dividing a high-frequency, intermediate signal (MSCLK) by 2. The ETU baud rate is created
by dividing MSCLK by 2 times the Fi/Di ratio specified by the codes below. For example, if FI = 0001 and
DI = 0001, the ratio of Fi/Di is 372/1. Thus the ETU divider is configured to divide by 2 * 372 = 744. The
maximum supported F/D ratio is 4096.
Table 92: Divider Ratios Provided by the ETU Counter
FI
(code)
0000 0001 0010 0011 0100 0101 0110 0111
Fi
(ratio)
372 372 558 744 1116 1488 1860 1860
⊕
FCLK
max
4 5 6 8 12 16 20 20
⊕
FI(code) 1000 1001 1010 1011 1100 1101 1110 1111
Fi(ratio)
512
⊕
512 768 1024
1536
2048 2048
⊕
2048
⊕
FCLK max 5
⊕
5 7.5
10
15
20 20
⊕
20
⊕
DI(code) 0000 0001 0010 0011 0100 0101 0110 0111
Di(ratio)
1
⊕
1 2 4 8 16 32 32
⊕
DI(code) 1000 1001 1010 1011 1100 1101 1110 1111
Di(ratio) 12
20
16
⊕
16
⊕
16
⊕
16
⊕
16
⊕
16
⊕
Note: values marked with
⊕
are not included in the ISO definition and arbitrary values have been
assigned.
The values given below are used by the ETU divider to create the ETU clock. The entries that are not
shaded will result in precise CLK/ETU per ISO requirements. Shaded areas are not precise but are
within 1% of the target value.