PS501 datasheet(17/42 Pages) MICROCHIP

17 / 42 page

 2004 Microchip Technology Inc.

DS21818C-page 17

PS501

Each condition in the table is processed by applying a

“comparison function” to the selected data (“condition

selection”) and the given constant (“condition thresh-

old”). The result of this operation (“true” or “false”) from

each condition in the group is combined as dictated by

the “AND-OR” “combination function” bit in the flag

byte. Because the “AND” function has precedence over

the “OR”, processing the CG can be described as

OR’ing subgroups of ANDs (see Example 7-1 below).

One 8-bit timer (clocked at 500 msec) is associated

with all 16 CSF(s). The timer compared to its threshold

is an implied “AND” term to the CG (i.e., if processing

of the CG to set the CSF results in “true”, the timer is

incremented and if timer >= threshold, the SF is set;

otherwise, the SF is not set even though the GC is sat-

isfied). If processing of the CG to set the CSF results in

“false”, the timer is set to zero. The timer is not allowed

to increment past the threshold.

The conditions in the order they are stored in memory

will build the activation equation until bit 7 of byte 1 is

set, signifying the last condition of the group. At that

point, the next group of conditions is the Reset

equation. When the next to last condition bit is set, a

new activation group begins.

EXAMPLE 7-1:

CONDITION GROUPS

TABLE 7-3:

CONDITIONS FOR EXAMPLE 7-1

Example Condition Group:

(VCELL-min < 3200) .AND. (CURR > 100) .OR. (TEMP > 60) .AND. (CURR > 200)

because of precedence the equation would be interpreted:

((VCELL-min < 3200) .AND. (CURR > 100)) .OR. ((TEMP > 60) .AND. (CURR > 200))

Example Reset Condition Group:

(VCELL-min > 3200) OR (CURR = 200)

Condition

Byte 1

Byte 2

Byte 3, 4

Description

x01

x42

x0C80

OR VCELL-min < 3200

x10

x0A

x0064

AND CURR > 100

x00

x08

x0D02

OR TEMP > 60°C (3330 degrees K * 10)

x80

x0A

x00C8

AND CURR > 200 (last condition bit set)

x00

x42

x0C80

OR VCELL-min > 3200

x82

x0A

x00C8

OR CURR = 200 (last condition bit set)

TABLE 7-4:

PARAMETERS

Name

Length

Description

SAFE_GPIO_MASK_00