Datasheet
MAX7315
8-Port I/O Expander with LED Intensity
Control, Interrupt, and Hot-Insertion Protection
18 ______________________________________________________________________________________
Table 10. PWM Application Scenarios
APPLICATION RECOMMENDED CONFIGURATION
All outputs static without PWM
Set the master, O8 intensity register 0x0E to any value from 0x00 to 0x0F.
The global intensity G bit in the configuration register is don't care.
The output intensity registers 0x10 through 0x13 are don't care.
A mix of static and PWM outputs, with PWM
outputs using different PWM settings
Set the master, O8 intensity register 0x0E to any value from 0x10 to 0xFF.
Clear global intensity G bit to 0 in the configuration register to disable global intensity
control.
For the static outputs, set the output intensity value to 0xF.
For the PWM outputs, set the output intensity value in the range 0x0 to 0xE.
A mix of static and PWM outputs, with PWM
outputs all using the same PWM setting
As above. Global intensity control cannot be used with a mix of static and PWM
outputs, so write the individual intensity registers with the same PWM value.
All outputs PWM using the same PWM
setting
Set the master, O8 intensity register 0x0E to any value from 0x10 to 0xFF.
Set global intensity G bit to 1 in the configuration register to enable global intensity
control.
The master, O8 intensity register 0x0E is the only intensity register used.
The output intensity registers 0x10 through 0x13 are don't care.
Figure 11. PWM Timing
ONE PWM PERIOD IS 240 CYCLES OF THE 32kHz PWM
OSCILLATOR. A PWM PERIOD CONTAINS 15 MASTER
INTENSITY TIMESLOTS
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 14 15 1 2
EACH MASTER INTENSITY
TIMESLOT CONTAINS 16
PWM CYCLES
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1615 16 1 2
Figure 12. Master Set to 1/15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 1514 15 21
.
Figure 14. Master Set to 15/15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 14 15 21
.
.
Figure 13. Master Set to 14/15
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 14 15 2 1
.
.