I have 2 problem with ade7753.
1- in ade7753 datasheet rev.c : page 21 figure 45 and 46
In this figures said for reading status register with reset we must use 0x05 command. But RSTSTATUS address is 0x0C as the datasheet said. Wich one is correct?
2- I want to use IRQ for reading values synhcronised by zerro crossing. I set corresponding bit in intrrupt enable register and do all thing looklike flowchart on figure 86 of datasheet. But no intrrupt is produced. I follow signal on IRQ pin by scope and saw that the pin is always low after power-on or reseting and initializing and every poll reading of RSTSTATUS has no effect on IRQ pin. Whats the problem?
I should say that i can read the IC in polling mode correctly(I mean checking zx bit in status register repeatly).Also I can detect zx in polling mode by reading RSTSTATUS repeatly. My problem is in intrrupt mode that mabe is related with my first question.
1. 0x0C RSTSTATUS is correct the diagram is wrong but the text and register list is correct.
2. Can you show me you circuit? Do you have a pull up on the IRQ Pin it is open collector.
Do you have any other IRQ enabled?
What are you writing to IRQEN 0x0A?
1- I Hope That Analog correct this in new version datasheet.
2- First I forgot about pull up resistor.After reading carefully I added a 10kOhm paralled with 220pF in pull up. But again no Interrupt. I add some delays in ISR code on micro and now I got interrupt sometimes.I mean its not a robust signal and sometimes crashes and i should reset all circuit by removing power supply and supply all circuit again. I think there is some noise on IRQ pin that in some circumstances it can generate correct interrupt and in some sutiations Not. I must mention below Notes:
A- My circuit is based on EVAL-ADE7753EB (ADE7753EB_0.pdf). IRQ and all SPI pins of ADE are connected to mirco via optocouplers (HCPL2631).
B- When I put scope probe on IRQ pin, there is no problem(scope is connected to Ground).
C- No I just enable ZX interrupt. I wrote 0x0C on MOD register and 0x10 on IRQEN register.
1- I will added it to the list for changes to the datasheet.
2. Without your actual schematic it will be difficult to help. The ADE7753 has been out for a very long time and installed in a large number of meters. If you are unwilling to share the entire schematic, can you share the circuit from IRQ pin of the ADE7753 to the micro?
A. Sometimes important pieces of the eval are removed when using this as an example.
B. Where did you scope the IRQ? Do you have a buffer between the IRQ pin and and the HCPL2631? The IRQ pin can't drive the LED in the opto.
1- Thanks alot.
2- No No. Its ok for me to share the schematics. I wiil put the image of this here and if you need I can also email it to you. This file has no pull up resistor and capacitor. I've added it manually befor RD6 resistor where labeled as "IRQ_ISO". When I put the scope on this node ( IRQ_ISO) the circuit works fine. I use tow buffer, 74HC125 and 74HCT244 as described on images below.
I've attached images of whole curcit's schematic and also the PCB layout below: