661
/
838
Nations Technologies Inc.
Tel
:
+86-755-86309900
:
Address: Nations Tower, #109 Baoshen Road, Hi-tech Park North.
Nanshan District, Shenzhen, 518057, P.R.China
Figure 23-22 ISO7816-3 Asynchronous Protocol
The break frame has no meaning in smart card mode. A 00h data with a framing error will be treated as data instead
of a break symbol.
Under normal operation, data will be shifted out of the transmit shift register on the next baud clock. The smart card
mode is delayed by a minimum of 1/2 baud clock than normal operation.
In normal operation, USART_STS.TXC is set when a frame containing data is sent and USART_STS.TXDE=1.In
smart card mode, the transmission completion flag (USART_STS.TXC) is set high when the guard time counter
reaches the value (USART_GTP.GTV[7:0]). The clearing of the USART_STS.TXC flag is not affected by the smart
card mode.
The following figure details how USART samples NACK signals.
S
0
1
2
3
4
5
6
7
P
S
0
1
2
3
4
5
6
7
P
Guard time
Guard time
Start
bit
Start
bit
Without Parity error
With Parity error
Line pulled low by
receiver during stop
In case of parity error