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TSC2000

SBAS257

TABLE VII. STS Bit Operation.

STS

READ/WRITE

VALUE

DESCRIPTION

Read

0

Converter is Busy

Read

1

Conversions are Complete, Data is Available

Write

0

Normal Operation

Write

1

Stop Conversion and Power Down

A/D3

A/D2

A/D1

A/D0

FUNCTION

0

0

0

0

Invalid. No registers will be updated. This is the default state after a reset.

0

0

0

1

Touch screen scan function: X and Y coordinates converted and the results returned to X and Y data registers.

Scan continues until either the pen is lifted or a stop bit is sent.

0

0

1

0

data registers. Scan continues until either the pen is lifted or a stop bit is sent.

0

0

1

1

Touch screen scan function: X coordinate converted and the results returned to X data register.

0

1

0

0

Touch screen scan function: Y coordinate converted and the results returned to Y data register.

0

1

0

1

0

1

1

0

Battery Input 1 converted and the results returned to the BAT1 data register.

0

1

1

1

Battery Input 2 converted and the results returned to the BAT2 data register.

1

0

0

0

Auxiliary Input 1 converted and the results returned to the AUX1 data register.

1

0

0

1

Auxiliary Input 2 converted and the results returned to the AUX2 data register.

1

0

1

0

A temperature measurement is made and the results returned to the temperature measurement 1 data register.

1

0

1

1

Port scan function: Battery Input 1, Battery Input 2, Auxiliary Input 1, and a Auxiliary Input measurements are made

and the results returned to the appropriate data registers.

1

1

0

0

A differential temperature measurement is made and the results returned to the temperature measurement 2 data

register.

1

1

0

1

Turn on X+, X– drivers.

1

1

1

0

Turn on Y+, Y– drivers.

1

1

1

1

Turn on Y+, X– drivers.

TABLE VIII. A/D Converter Function Select.

PSM

READ/WRITE

VALUE

DESCRIPTION

Read

0

No Screen Touch Detected

Read

1

Screen Touch Detected

Write

0

Conversions Controlled by Host

Write

1

Conversions Controlled by TSC2000

TABLE V. PSM Bit Operation.

MSB

LSB

BIT 15

BIT 14

BIT 13

BIT 12

BIT 11

BIT 10

BIT 9

BIT 8

BIT 7

BIT 6

BIT 5

BIT 4

BIT 3

BIT 2

BIT 1

BIT 0

PSM

STS

AD3

AD2

AD1

AD0

RS1

RS0

AV1

AV0

CL1

CL0

PV2

PV1

PV0

X

TABLE VI. A/D Converter Control Register.

RS1

RS0

FUNCTION

0

0

12-Bit Resolution. Power up and reset default.

0

1

8-Bit Resolution

1

0

10-Bit Resolution

1

1

12-Bit Resolution

TABLE IX. A/D Converter Resolution Control.

TSC2000 A/D CONVERTER CONTROL REGISTER

The A/D converter in the TSC2000 is shared between all the

different functions. A control register determines which input

is selected, as well as other options. The result of the

conversion is placed in one of the result registers in Page 0

of memory, depending upon the function selected.

The A/D Converter Control Register controls several aspects

of the A/D converter. The register is formatted as shown in

Table VI.

Bit 15: PSM—Pen Status/Control Mode. Reading this bit

allows the host to determine if the screen is touched. Writing

to this bit determines the mode used to read coordinates:

host controlled, or under control of the TSC2000 responding

to a screen touch. When reading, the PENSTS bit indicates

if the pen is down or not. When writing to this register, this bit

determines if the TSC2000 controls the reading of coordi-

nates, or if the coordinate conversions are host-controlled.

The default state is host-controlled conversions (0).

Bit 14: STS—A/D Converter Status. When reading this bit

indicates if the converter is busy, or if conversions are

complete and data is available. Writing a 0 to this bit will

cause touch screen scans to continue until either the pen is

lifted or the process is stopped. Continuous scans or conver-

sions can be stopped by writing a 1 to this bit. This will

immediately halt a conversion (even if the pen is still down)

and cause the A/D converter to power down. The default

state is continuous conversions, but if this bit is read after a

reset or power-up, it will read 1.

Bits [13:10]: AD3–AD0—A/D Converter Function Select

Bits. These bits control which input is to be converted, and

what mode the converter is placed in. These bits are the

same whether reading or writing. A complete listing of how

these bits are used is shown in Table VIII.

Bits[9:8]: RS1, RS0—Resolution Control. The A/D converter

resolution is specified with these bits. A description of these

bits is shown in Table IX. These bits are the same whether

reading or writing.