Philips Semiconductors
AN10369
Philips ARM LPC microcontroller family
•
Slave address
•
Data byte
In the code three port indicators were used which are shown in the waveforms below. For
instance consider I
2
C state 8H.
void ISR_8()
{
/* Port Indicator */
IOCLR=0x10;
…………….
IOSET=0x10;
}
The results of the two statements are shown in the oscilloscope as channel D3 (labeled
S_8). Similarly, D4 indicates state 18H and D5 indicates state 28H.
Channel D2 shows all the instances when the IRQ interrupt is triggered and normal
program flow (i.e. while(1) loop in C main()) is interrupted and IRQ interrupts are
serviced. Channel D1 and channel D0 indicate SDA and SCLK respectively.
Fig 5. Waveforms
© Koninklijke Philips Electronics N.V. 2005. All rights reserved.
Application note
Rev. 01 — 06 April 2005
15 of 17