Datasheet

ADS7950, ADS7951, ADS7952, ADS7953

ADS7954, ADS7955, ADS7956, ADS7957

ADS7958, ADS7959, ADS7960, ADS7961

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SLAS605A –JUNE 2008–REVISED JANUARY 2010

Table 9. Alarm Program Register Settings (continued)

DESCRIPTION

BITS RESET STATE

LOGIC

FUNCTION

STATE

DI15-14 NA cc Where “cc” represents the lower two bits of the channel number in binary format. The device

programs the alarm for the channel represented by the binary number “bbcc”. Note that “bb” is

programmed in the first frame.

DI13 NA 1 High alarm register selection

0 Low alarm register selection

DI12 NA 0 Continue alarm programming sequence in next frame

1 Exit Alarm Programming in the next frame. Note: If the alarm programming sequence is not

terminated using this feature then the device will remain in the alarm programming sequence

state and all SDI data will be treated as alarm thresholds.

DI11-10 NA xx Do not care

DI09-00 All ones for high This 10-bit data represents the alarm threshold. The 10-bit alarm threshold is compared with the upper 10-bit

alarm register word of the 12-bit conversion result. The device sets off an alarm when the conversion result is higher (High

and all zeros for Alarm) or lower (Low Alarm) than this number. For 10-bit devices, all 10 bits of the conversion result are

low alarm register compared with the set threshold. For 8-bit devices, all 8 bits of the conversion result are compared with DI09

to DI02 and DI00, 01 are 'do not care'.

PROGRAMMING GPIO REGISTERS

NOTE

GPIO 1 to 3 are available only in TSSOP packaged devices. The QFN device offers

'GPIO 0' only. As a result, all references related to 'GPIO 0' only are valid in the case

of QFN package devices.

The device has four General Purpose Input and Output (GPIO) pins. Each of the four pins can be independently

programmed as General Purpose Output (GPO) or General Purpose Input (GPI). It is also possible to use the

GPIOs for some pre-assigned functions (refer to Table 10 for details). GPO data can be written into the device

through the SDI line. The device refreshes the GPO data on every CS falling edge as per the SDI data written in

the previous frame. Similarly, the device latches GPI status on the CS falling edge and outputs it on SDO (if GPI

is read enabled by writing DI04 = 1 during the previous frame) in the same frame starting on the CS falling edge.

The details regarding programming the GPIO registers are illustrated in the flowchart in Figure 56. Table 10 lists

the details regarding GPIO Register programming settings.

Product Folder Link(s): ADS7950, ADS7951, ADS7952, ADS7953 ADS7954, ADS7955, ADS7956, ADS7957 ADS7958,

ADS7959, ADS7960, ADS7961