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TLC32040C Datasheet, PDF (13/33 Pages) Texas Instruments – ANALOG INTERFACE CIRCUITS | |||
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TLC32040C, TLC32040I, TLC32041C, TLC32041I
ANALOG INTERFACE CIRCUITS
SLAS014E â SEPTEMBER 1987 â REVISED MAY 1995
power-up sequence
To ensure proper operation of the AIC, and as a safeguard against latch-up, it is recommended that a Schottky
diode with a forward voltage less than or equal to 0.4 V be connected from VCC â to ANLG GND (see Figure 17).
In the absence of such a diode, power should be applied in the following sequence: ANLG GND and DGTL GND,
VCC â, then VCC + and VDD. Also, no input signal should be applied until after power up.
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. TAâ 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. RAâ register can be either positive, negative, or zero.
7. (TA register ± TAâ register) must be > 1.
8. (RA register ± RAâ register) must be > 1.
9. TB register must be > 1.
Table 1. AIC Responses To Improper Conditions
IMPROPER CONDITIONS
TA register + TAâ register = 0 or 1
TA register â TAâ register = 0 or 1
TA register + TAâ register < 0
RA register + RAâ register = 0 or 1
RA register â RAâ register = 0 or 1
RA register + RAâ register = 0 or 1
TA register = 0 or 1
RA register = 0 or 1
TA register < 4 in word mode
TA register < 5 in byte mode
RA register < 4 in word mode
RA register < 5 in byte mode
TB register = 0 or 1
RB register = 0 or 1
AIC and DSP cannot communicate
AIC RESPONSE
Reprogram TX counter A with TA register value
MODULO 64 arithmetic is used to ensure that a positive value is loaded into the TX counter A, i.e., TA
register + TAâ register + 40 hex is loaded into TX counter A.
Reprogram RX counter A with RA register value
MODULO 64 arithmetic is used to ensure that a positive value is loaded into RX counter A, i.e., RA
register + RAâ register + 40 hex is loaded into RX counter A.
The AIC is shut down.
The AIC serial port no longer operates.
Reprogram TB register with 24 hex
Reprogram RB register with 24 hex
Hold last DAC output
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