TLC32040M

ANALOG INTERFACE CIRCUIT

POST OFFICE BOX 655303

4–9

power-up sequence

To ensure proper operation of the AIC and as a safeguard against latch-up, it is recommended that a Schottky

In the absence of such a diode, power should be applied in the following sequence: ANLG GND and DGTL GND,

AIC responses to improper conditions

The AIC has provisions for responding to improper conditions. These improper conditions and the response of

the AIC to these conditions are presented in Table 1 below.

AIC register constraints

The following constraints are placed on the contents of the AIC registers:

1. TA register must be

≥ 4 in WORD mode (WORD/BYTE = high).

2. TA register must be

≥ 5 in BYTE mode (WORD/BYTE = low).

3. TA’ register can be either positive, negative, or zero.

4. RA register must be

≥ 4 in WORD mode (WORD/BYTE = high).

5. RA register must be

≥ 5 in BYTE mode (WORD/BYTE = low).

6. RA’ register can be either positive, negative, or zero.

7. (TA register

± TA’ register) must be > 1.

8. (RA register

± RA’ register) must be > 1.

9. TB register must be > 1.

Table 1. AIC Responses to Improper Conditions

IMPROPER CONDITION

AIC RESPONSE

TA register + TA’ register = 0 or 1

TA register – TA’ register = 0 or 1

Reprogram TX Counter A with TA register value

TA register + TA’ register < 0

MODULO 64 arithmetic is used to ensure that a positive value is loaded into the TX Counter A,

i.e., TA register + TA’ register + 40 HEX is loaded into TX Counter A.

RA register + RA’ register = 0 or 1

RA register – RA’ register = 0 or 1

Reprogram RX Counter A with RA register value

RA register + RA’ register = 0 or 1

MODULO 64 arithmetic is used to ensure that a positive value is loaded into the RX Counter

A, i.e., RA register + RA’ register + 40 HEX is loaded into RX Counter A.

TA register = 0 or 1

RA register = 0 or 1

AIC is shutdown.

TA register < 4 in WORD mode

TA register < 5 in BYTE mode

RA register < 4 in WORD mode

RA register < 5 in BYTE mode

The AIC serial port no longer operates.

TB register = 0 or 1

Reprogram TB register with 24 HEX

RB register = 0 or 1

Reprogram TB register with 24 HEX

AIC and DSP cannot communicate

Hold last DAC output