LM8333EVALKIT National Semiconductor, LM8333EVALKIT Datasheet - Page 7

• Manufacturer Part Number: LM8333EVALKIT
• Description: BOARD EVALUATION LM8333
• Manufacturer: National Semiconductor

Specifications of LM8333EVALKIT

• Main Purpose: Interface, Special Purpose
• Embedded: Yes, MCU, 8-Bit
• Utilized Ic / Part: LM8333
• 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: Not applicable / Not applicable

9.2 I/O EXPANSION
In addition to keypad scanning, the LM8333 supports various
I/O expansion options.
9.2.1 PWM Output with Programmable Duty Cycle
The PWM pin may be used either as a pulse-width modulated
output driven by a 16-bit timer or as a general-purpose output
pin. In the PWM mode, the low time (T
(T
in which t
shown in
The PWM_LO command writes T
mand writes T
Event Number
HI
) are programmable between 1 × t
1
2
3
4
5
6
7
8
Figure
C
is the cycle time (nominally 1 microsecond), as
HI
3. The period T
. Operational modes of the PWM pin are
Event Code
0xB6
0xB4
0xF1
0x71
0x36
0x34
0x91
0x00
FIGURE 4. PWM Control Commands for Arbitrary Duty Cycle
PD
LO
FIGURE 2. Example Event Codes Loaded in FIFO Buffer
is the sum of T
, and the PWM_HI com-
C
and 65K × t
LO
TABLE 2. Example Sequence of Events
) and high time
Event on Input
Wake_INP7
Wake_INP3
Wake_INP7
Wake_INP3
Wake_INP3
Wake_INP3
Wake_INP1
HI
NA
and T
C
cycles
LO
.
7
controlled by the PWM_CTL command. Before activating the
PWM output, the T
4
Matrix Node
shows the command formats.
K_OUT0
K_OUT5
K_OUT0
K_OUT5
K_OUT3
K_OUT3
K_OUT0
NA
FIGURE 3. Programmable PWM
LO
Key is pressed
Key is pressed
Key is released
Key is released
Key is pressed
Key is released33
Key is pressed
Indicates end of stored events
and T
HI
times must be initialized.
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