gpio speed
I have an LPC2138 running at 60MHz. However, when I toggle the I/O pins repeatedly (using IOxSET,IOxCLR, or even IOPIN instructions), e.g.
IO0SET = 0x01
IO0CLR = 0x01
IO0SET = 0x01
IO0CLR = 0x01
IO0SET = 0x01
IO0CLR = 0x01
IO0SET = 0x01
IO0CLR = 0x01
The port toggles only at about 160nS between instructions. The resulting assembly shows no extra instructions, and I have also set the GPIO divider VPBDIV to 1. So theoretically the port should be operating at core speed, but it is only running at about a tenth of that.
Is there an intrinsic I/O limitation in LPC parts, or is there a way to run the I/O ports at a higher rate?
Thanks