LM8333 datasheet(7/17 Pages) NSC

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7.0 Device Operation (Continued)

TABLE 2. Example Sequence of Events

Event Number

Event Code

Event on Input

Matrix Node

Description

0xF1

Wake_INP7

K_OUT0

Key is pressed

0xB6

Wake_INP3

K_OUT5

Key is pressed

0x71

Wake_INP7

K_OUT0

Key is released

0x36

Wake_INP3

K_OUT5

Key is released

0xB4

Wake_INP3

K_OUT3

Key is pressed

0x34

Wake_INP3

K_OUT3

Key is released33

0x91

Wake_INP1

K_OUT0

Key is pressed

0x00

Indicates end of stored events

7.2 I/O EXPANSION

In addition to keypad scanning, the LM8333 supports vari-

ous I/O expansion options.

7.2.1 PWM Output with Programmable Duty Cycle

The PWM pin may be used either as a pulse-width modu-

lated output driven by a 16-bit timer or as a general-purpose

output pin. In the PWM mode, the low time (T

LO) and high

time (T

HI) are programmable between1xtC and 65K x tC

cycles in which t

C is the cycle time (nominally 1 microsec-

ond), as shown in Figure 3. The period T

PD is the sum of THI

and T

LO. The PWM_LO command writes TLO, and the PW-

M_HI command writes T

HI. Operational modes of the PWM

pin are controlled by the PWM_CTL command. Before acti-

vating the PWM output, the T

LO and THI times must be

initialized. Figure 4 shows the command formats.

20210604

FIGURE 2. Example Event Codes Loaded in FIFO Buffer

20210605

FIGURE 3. Programmable PWM

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