Version 2 (modified by 15 years ago) ( diff ) | ,
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Programming Neo FreeRunner LEDs
Neo FreeRunner has three LED indicators:
Color | Location | IO Port/pin |
orange | behind power button | GPB0 |
blue | behind power button | GPB1 |
red | behind aux button | GPB2 |
Combination of orange and blue behind the power button should give purple.
Port B Control Registers
Register | Address | Description | Reset value |
GPBCON | 0x56000010 | Pin configuration | 0x0 |
GPBDAT | 0x56000014 | Data in/out | undefined |
GPBDN | 0x56000018 | Pull-down disable | 0x0 |
GPB has 11 pins (GPB0 through GPB1 inclusive).
Register descriptions:
- GPBCON: Two configuration bits per pin (GPBCON[1:0] for GPB0, GPBCON[3:2] for GPB1, etc.), 00 = Input, 01 = Output, 10 = XXX, 11 = reserved. XXX refers to internal signals, different for each pin.
- GPBDAT: Obvious, write in output mode and read in input mode.
- GPBDN[10:0]: 0 = pull-down enabled, 1 = pull-down disabled.
For blinking LEDs, we select output mode (0b01) for GPB0..GPB2. Pull-down should be disabled. Then write to GPBDAT[0:2].
References:
- Samsung S3C2442B Processor Datasheet Port B Control Registers, Page 9-10.
- Neo FreeRunner Schematics MCU, sheet 3.
Notes:
- Not verified
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