KS152JB Universal Communications Controller Technical Specifications
3.5.11 External Clocking
To select external clocking, the user is given three choices. External clocking can be used with the transmitter, with the receiver, or with both. To select external clocking for the transmitter, XTCLK (GMOD.7) has to be set to a 1. To select external clocking for the receiver, XRCLK (PCON.3) has to be set to a 1. Set ting both bits to 1 forces external clocking for the receiver and transmitter. The minimum frequency the GSC can be externally clocked at is 0 Hz (D.C.).
The external transmit clock is applied to pin 4 (TXC), P1.3. The external receive clock is applied to pin 5 (RXC), P1.4. To enable the external clock function on the port pin, that pin has to be set to a 1 in the appropriate SFR, P1.
Whenever the external clock option is used, the format of the transmitted and received data is restricted to NRZ encoding and the protocol is restricted to SDLC. With external clock, the bit stuffing/stripping is still active with SDLC protocol.
3.5.12 Determining Receiver Errors
It is possible that several receiver error bits will be set in response to a single cause. The multiple errors that can occur are:
AE and CRCE may both be set when an alignment error occurs due to a bad CRC caused by the misaligned frame.
RCABT, AE, and CRCE may be set when an abort occurs.
OVR, AE, and CRCE may be set when a overrun occurs.
In order to determine the correct cause o the error a specific order should be followed when exam- ining the error bits. This order is:
1)OVR
2)RCBAT
3)AE
4)CRCE
3.5.13Addressing
There are four
The C152 can have up to four different
Kawasaki LSI USA, Inc. | Page 64 of 120 | Ver. 0.9 KS152JB2 |