Host Port Emulation - This provides a bus interconnection between the call processor and the DSP via the call processor' s parallel memory bus, interconnected to the

modem DSP' s parallel memory bus. This communications port is functionally identical to the host port provided for the Motorola DSP; To both devices, the port

appears as a bus-mapped peripheral. The call processor sees the port as an 8-address block in memory at a location determined by the call processor' s programming

of its own chip select for the START IC. The DSP sees the port as an 8-address block in I/O space. Because the STUART IC uses the high byte of the DSP' s bus,

provisions are made for byte/word conversion, to be compatible with the existing word-wide communications with U1000(Call processor).

DSP Timer - It provides a timer function. This is a device, accessible to the DSP, which implement a continuously clocked timer, with rollover, a feature needed for

modem functionality but difficult to implement with the ATT device. The ATT timer can be set up to either stop on count=0, or to repeat the last count interval. We

need a counter that can be set up to interrupt at a particular point in time, and then keeps counting, so that real-time is preserved, and can be set for a future time

interval. This timer has a clock that is coherent with the symbol rate.

General Purpose I/O - It provides a 4-bit general purpose I/O port, with programming data direction function, as an extension to the call processor bit I/O set.

RF SPI interface - Improved interface between the Call processor, DSP, and ZIFSYN for scanning requirements needed because of the PCS band

Transmitter control logic - Transmitter keying and frequency band selection.

Table of Contents