Texas Instruments TMS320C3 Series, User Manual, Page: 53 / 166

TLC32040 AIC Initialization
4-19 Functional Overview
Figure 4–9 describes the control register bit fields.
Figure 4–9. Control Register Bit Fields
D7 D6 D5 D4 D3 D2
Input Gain Transmit/Receive AUX IN Pins
Loopback
Function Bandpass
Filter
0 0 = 1X for
"
6V analog input 0 = asynchronous 0 = disables 0 = disables 0 = deletes
0 1 = 2X for
"
3V analog input 1 = enables 1 = enables 1 = enables 1 = inserts
1 0 = 4X for
"
1.5V analog input
1 1 = 1X for
"
6V analog input
The assembly code in Example 4–2 sets the TA and TB registers of the AIC.
This code transmits a 16-bit word to the AIC and then waits until the transmit
interrupt is generated by the serial port. Four commands are transmitted start-
ing with a 0, then the TB and RB values, followed by the TA and RA values,
and finally the control word. TA and RA values should be the last values trans-
mitted, since they change the AIC sample rate. By transmitting these values
last, the sample rate is not changed until the AIC receives the last program
word. In this way, very high sample rates can be achieved. Each command
transmits three 16-bit words: a primary communication, a secondary commu-
nication, and a 0-data word.