Gpio Usage Notes - Philips LPC2119 User Manual

Philips Semiconductors
ARM-based Microcontroller
GPIO Direction Register (IO0DIR - 0xE0028008, IO1DIR - 0xE0028018)
This register is used to control the direction of the pins when they are configured as GPIO port pins. Direction bit for any pin must
be set according to the pin functionality.
Table 72: GPIO Direction Register (IO0DIR - 0xE0028008, IO1DIR - 0xE0028018)
IODIR
Direction control bits (0 = INPUT, 1 = OUTPUT). Bit 0 in IO0DIR controls P0.0 ... Bit 31 in IO0DIR
31:0
controls P0.31

GPIO USAGE NOTES

If for the specified output pin corresponding bit is set both in GPIO Output Set Register (IOnSET) and in GPIO Output Clear
Register (IOnCLR), observed pin will output level determined by the later write access of IOnSET nad IOnCLR. This means that
in case of sequence:
IO0SET = 0x0000 0080
IO0CLR = 0x0000 0080
pin P0.7 will have low output, since access to Clear register came after access to Set register.
GPIO
Description
109
Preliminary User Manual
LPC2119/2129/2292/2294
Value after
January 08, 2004
Reset
0