Motorola MPC8260 User Manual

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MOTOROLA

5. Clear TEND for default operation.

6. Set TPP to 0b11 for a preamble pattern of all ones.

7. Set TPL to 0b000 to transmit the next frame with no synchronization sequence and 

to 001 to transmit the next frame with the LocalTalk synchronization sequence. For 
example, data frames do not require a preceding synchronization sequence. These 
bits may be modiÞed on-the-ßy if the AppleTalk protocol is selected.

8. Clear TINV and RINV so data will not be inverted. 

9. Set TSNC to 1.5 bit times (0b10).

10. Clear EDGE. Both the positive and negative edges are used to change the sample 

point (default).

11. Clear RTSM (default).

12. Set all other bits to zero or default.

13. Set ENT and ENR as the last step to begin operation.

Follow these steps to program the protocol-speciÞc mode register:

1. Set NOF to 0b0001 giving two ßags before frames (one opening ßag, plus one 

additional ßag).

2. Set CRC 16-bit CRC-CCITT.

3. Set DRT.

4. Set all other bits to zero or default.

For the PSMR deÞnition, see Section 21.8, ÒHDLC Mode Register (PSMR).Ó

Use the transmit-on-demand (TODR) register to expedite a transmit frame. See
Section 19.1.4, ÒTransmit-on-Demand Register (TODR).Ó

Except for the previously discussed register programming, use the example in
Section 21.14.6, ÒHDLC Bus Protocol Programming.Ó