LM8322EVALKIT National Semiconductor, LM8322EVALKIT Datasheet - Page 27

• Manufacturer Part Number: LM8322EVALKIT
• Description: BOARD EVALUATION LM8322
• Manufacturer: National Semiconductor

Specifications of LM8322EVALKIT

• Main Purpose: Interface, Special Purpose
• Embedded: No
• Utilized Ic / Part: LM8322
• Primary Attributes: Mobile I/O Companion with Key-Scan, I/O Expansion, PWM, Access.bus Host
• Secondary Attributes: Board has MCU for USB to PC GUI
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

16.7 INTERRUPT CODE
The interrupt code is read and acknowledged with the
READ_INT command (0x82). This command clears the code
16.8 ERROR CODE
If the LM8322 reports an error, the READ_ERROR command
(0x8C) is used to read the error code. This command clears
the error code. Table 14 shows the format of the error code.
16.9 WAKE-UP FROM HALT MODE
Any bus transaction initiated by the host may encounter the
LM8322 device in Halt mode or busy with processing data,
such as controlling the FIFO buffer or executing interrupt ser-
vice routines.
Figure 18 shows the case in which the host sends a command
while the LM8322 is in Halt mode (Internal execution clock is
stopped). Any activity on the ACCESS.bus wakes up the
LM8322, but it cannot acknowledge the first bus cycle imme-
diately after wake-up.
The host drives a Start condition followed by seven address
bits and a R/W bit. The host then releases SDA for one clock
period, so that it can be driven by the LM8322.
If the LM8322 does not drive SDA low during the high phase
of the clock period immediately after the R/W bit, the bus cycle
PWM2END
7
0
7
FIFOOVER
PWM2END
PWM1END
PWM0END
CMDUNK
KEYOVR
BADPAR
KEYPAD
ERROR
NOINIT
Bit
Bit
FIFOOVR
6
PWM1END
FIGURE 18. LM8322 Responds with NACK, Host Retries Command
6
Event occurred while the FIFO was full.
More than two keys were pressed simultaneously.
Not a valid command.
Bad command parameter.
An END script command was executed by PWM channel 2.
An END script command was executed by PWM channel 1.
An END script command was executed by PWM channel 0.
The LM8322 is waiting for an initialization sequence.
An error condition occurred.
A key-press or key-release event occurred.
5
0
PWM0END
TABLE 13. Interrupt Code
5
4
0
TABLE 14. Error Code
27
3
0
NOINIT
and deasserts the IRQ output. Table 13 shows the format of
the interrupt code.
terminates without being acknowledged (shown as NACK in
Figure 18). The host then aborts the transaction by sending
a Stop condition. After aborting the bus cycle, the host may
then retry the bus cycle. On the second attempt, the LM8322
will be able to acknowledge the slave address, because it will
be in Active mode.
Alternatively, the I
byte (00000001), which will not be acknowledged by any de-
vice. This byte can be used to wake up the LM8322 from Halt
mode. The LM8322 may also stall the bus transaction by
pulling the SCL low, which is a valid behavior defined by the
I
2
4
C specification.
Description
KEYOVR
Description
2
ERROR
3
2
C specification allows sending a START
CMDUNK
2
0
1
30013618
1
0
BADPAR
KEYPAD
0
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0