Motorola Timeport P8190, Service Manual

Page: 132 / 149

TDMA StarTAC
TM
P8190: STUART(U1700)
A
34
Description
The STUART IC(U1700) is a custom gate array that uses the following functions.
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.
BLOCK DIAGRAM NOT NECESSARY
REFER TO PAGE B35