The assignment of the RS232 port is shown below

B7

B6

B5

B4

B3

B2

B1

B0

COM1

Input Address

3FE

X

X

X

CTS

X

X

X

X

Output Address

3FC

X

X

X

0

X

X

RTS

DTR

shown on the next page. The program prompts for data

mode select instruction to be sent to the A/D. This can be

found from the Mode Programming table shown earlier. The

data should be entered in “1”s and “0”s as shown in the table

with DI0 first. Next the program prompts for the number of

SCLKs required for the programmed mode select instruction.

For instance, to send all “0”s to the A/D, selects CH0 as the

+input, CH1 as the −input, 12-bit conversion, and 13-bit MSB

first data output format (if the sign bit was not turned off by a

previous instruction). This would require 13 SCLK periods

since the output data format is 13 bits. The part powers up

with No Auto Cal, No Auto Zero, 10 CCLK Acquisition Time,

12-bit conversion, data out with sign, 12- or 13-bit MSB First,

power up, and user mode. Auto Cal, Auto Zero, Power UP

and Power Down instructions do not change these default

settings. The following power up sequence should be fol-

lowed:

1.

Run the program

2.

Prior to responding to the prompt apply the power to the

ADC12L038

3.

Respond to the program prompts

It is recommended that the first instruction issued to the

ADC12L038 be Auto Cal (see Section 1.1).

DS011830-45

D

REF

caps. The DS14C335 has an internal DC-DC converter that generates the necessary TIA/EIA-232-E output levels from a 3.3V supply. There are four 0.47 µF

capacitors required for the DC-DC converter that are not shown in the above schematic.

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