T = 1 Smartcards - Motorola DragonBall MC9328MX1 Reference Manual

SmartCard Interface Module (SIM)
4. Adjust the stop clock polarity by modifying the value of the SCSP bit in the PORT_CNTL
register.
5. Adjust the level of transmit NACK retransmissions allowed by modifying the value of the
XTH bits in the XMT_THRESHOLD register.
When a negotiation with the SmartCard is desired, the software sends a PPS response to the SmartCard. To
send the response, the following steps must be performed:
1. Set the desired transmit FIFO threshold level by writing the TDT bits in the
XMT_THRESHOLD register.
2. Write the characters to be sent as response (maximum 16) to the transmit FIFO through the
XMT_BUF register.
3. Clear all transmit interrupt flags in the XMT_STATUS register by writing 1 to them.
4. Enable the transmit interrupts desired by clearing the mask bits in the INT_MASK register.
When sending more than 16 characters, using the TDTF interrupt to signify when to write
more characters to the transmit FIFO results in the most efficient transfer times to the
SmartCard.
5. Enable the transmitter by setting the XMT_EN bit in the ENABLE register.
At this point, the SIM transmits the characters in the transmit FIFO. When sending more than 16
characters, the transmit threshold interrupt is set when the threshold number of characters are remaining in
the FIFO. The software can then write an additional number of characters to be sent without interrupting
transmission to the SmartCard.
When the transmission is complete, the SIM must be completely configured for standard operation with
the T = 0 SmartCard. The software can continue to service RDRF interrupts for received characters, and
TDTF interrupts for transmitted characters.

25.10.2.3 T = 1 SmartCards

When the card type is T = 1, the software must adjust the following parameters according to the
information in the ATR:
1. Adjust the baud rate by changing the values of the BAUD_SEL bits in the CNTL register.
2. Adjust the guard time between characters by changing the value of GETU in the
GUARD_CNTL register. Setting GETU to 0xFF configures the SIM transmitter for 11
ETU transmissions.
3. Disable NACK capability by clearing the ONACK and ANACK bits in the CNTL register.
T = 1 cards do not allow NACKs.
4. Adjust the stop clock polarity by modifying the value of the SCSP bit in the PORT_CNTL
register.
5. Set Character Wait Time Counter Comparator to the value specified in the ATR in the
CHAR_WAIT register.
6. Enable the Character Wait Time Counter Interrupt by clearing CWTM in the INT_MASK
register.
7. Enable the Character Wait Time Counter by setting the CWTEN bit in the CNTL register.
8. Enable CRC or LRC error checking according to the ATR information by setting either the
CRCEN or LRCEN bit in the CNTL register. These bits must never be set at the same time.
For T = 1 cards, the ATR is sent through a T = 0 type of structure (12 ETU, no LRC or CRC). When a
negotiation with the SmartCard is desired, the software sends a PPS response to the SmartCard. Otherwise,
25-54 MC9328MX1 Reference Manual MOTOROLA