Analog Integrated Circuit Device Data

Freescale Semiconductor

33

33937

FUNCTIONAL DEVICE OPERATION

LOGIC COMMANDS AND REGISTERS

NULL COMMANDS

This command is sent by sending binary 000x xxxx data. This can be used to read IC status in the SPI return word. Message

000x xx00 reads Status Register 0. Message 000x xx01 through 000x xx11 read additional internal registers.

MASK Command

This is the mask for interrupts. A bit set to “1” enables the corresponding interrupt. Because of the number of MASK bits, this

register is in two portions:

1. MASK0

2. MASK1

Both are accessed with 0010 xxxx and 0011 xxxx patterns respectively. Figure 20 illustrates how interrupts are enabled and

faults cleared.

CLINT0 and CLINT1 have the same format as MASK0 and MASK1 respectively, but the action is to clear the interrupt latch

and status register 0 bit corresponding to the lower nibble of the command.

INTERRUPT HANDLING

Figure 20. Interrupt Handling

Table 8. NULL Commands

SPI Data Bits

765

432

10

Write

000

x

x

x

0

0

Reset

NULL Commands are described in detail in the STATUS REGISTERS section of this document.

Table 9. MASK0 Register

SPI Data Bits

765

432

10

Write

001

0

x

x

x

x

Reset

11

11

Table 10. MASK1 Register

SPI Data Bits

765

432

10

Write

001

1

x

x

x

x

Reset

11

11

To Status Register

Various Faults

From Clint Command

From MASKx:N Register

Fault

net 0

net N

INT

INT Clear

INT Source

S

R

Latch