Logic Analyzer

[dragondgold]

Hi, i am doing a logic analyzer whit a uLCD-32PT and i wold like to have some specs of the LCD. Is there any way to generate a delay less than 1mS? Somehing like NOP? Which is the speed of the Picasso at MIPS? How fast can the outputs be switched and how much current can they source/sink?I need to generate delays less than 1mS to do the clock for analyzing the signals i receive because they are asynchronous (USART,I2C).Any idea woul be aprecciated
Thanks

[meldavia]

You can generate a delay shorter than 1msec, but the first problem you come up against
is the fact that the display has various interrupts running internally for touch
screen, comms, and timers so whatever you do, you will have problems.
Best way to do a logic analyser is to have another micro or FPGA to do the real
time capturing, and pass the real time buffered info to the display.

[dragondgold]

If i disable timer events, touchscreen and COM ports will be any problem?

[dragondgold]

No answer?? I am still interested in creating that delays...
Thanks

[ESPsupport]

It's basically what Meldavia said.

You can turn off Touch and Comms interrups, but you can't turn off the Timers (with any degree of certaintly)

[dragondgold]

But why the timers interrupts are needed? I knew there is only one kind of timer interrupts which call a function whit it reachs 0. So its imposible?
Thanks

[ESPsupport]

Well that interrupt is the 'end of timer' interrupt.

There's still the interrupt that services the timer. That runs all the time as there would be too much latency if it was started and stopped 'as needed'. That's what will cause the problem.

[dragondgold]

How much latency are we talking about? 10 seconds? 100mS ? Because i dont need it to me very fast to init, i mean i would disable the timer when enter in mode only and turn it on again when i exit

[meldavia]

There is no way you can have any synchronous operations. The display uses an RTOS that is asynchronous by nature.
There are many interrupts occurring 'under the hood' in the display. It is impossible to take control of internal timer events and services.
You will need to use a secondary processor to capture input for your .

[dragondgold]

Hoooo i didnt know the LCD uses and RTOS ok thanks for the support .
PD: the RTOS was developed by 4D ??

[meldavia]

yes developed by 4D, actually RTOS puts it into a category, but realistically RTOS is a fairly loose term for 'custom framework handling time sharing for multiple events'
such as:-

• Scanning or touch screen and filtering noise
• Blitting images to GRAM windows on screenHandling Timer event queue'sHandling communications interrupts

etc etc