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I am working with ATOM PRO 64 TQFP mounted on a carrier board and connected as per circuit shown on the sixth page of the B0261 data sheet. THE A/D PINS DO NOT SEAM TO WORK IN A/D MODE. These pins do respond to HIGH and LOW and do output SOUND (to a ‘scope). Math functions, debug, etc. etc. all appear to work OK and programs written for the ATOM PRO 40 that don’t use A/D all appear to work ok on the PRO 64 TQFP.

Even the simplest A/D program (manual page 86) give an A/D reading of 0. I tried P0 (physical pin 13) and P29 (physical pin 48). Of course I checked the actual voltage at the pin (about 3V). AVcc is at 5V. Same program on PRO 40 works fine.

Am using the latest STUDIO with “Basic ATOM PRO” and “Auto” selected and it automatically detects BAPIC642-20. Programming sequence seams normal (same as PRO 40). Am using the transistor based RS232 converter shown in the PRO 40 data sheet for programming.

Does anyone have any Ideas as to what my problem is?

Could the problem be in the subtleties of the module selection and programming protocol (of which I have no information)? I note that the reset circuits for the PRO 40 and PRO 64 are different as shown on the data sheets, particularly the location of the diode, and I am not sure exactly what circuit is required at the RESET pin. Is the “drain diode” referred to in the data sheet the D1 shown on the schematic or is an additional diode required? Why is the “external pull-up” referred to on the data sheet not shown on the schematic? I am focusing my thoughts on the reset pin as Dale told me a few weeks ago that the diode on the reset pin is critical and that weird stuff can happen if it isn’t correct.

Thanks in anticipation of some help and ideas as to where to look further,
Peter Strong

use pins p40 to 47 with the compiler and they are physical pins 1, 2, 59 - 64.

Thanks Mike, all is working fine now .

The Data Sheet B0261 for the ATOM Pro 64 TQFP needs revision to reflect this...BM take note.

The Data sheet shows the A/D ports under the label P0 to P3 and P28 to P31. These do not work for A/D. The data sheet also correctly shows the A/D ports under P40 to P47 which work fine.

The ATOM Pro 40 connects some ports together to meet the limit of only 40 physical pins on the module. The Pro 64 has no such limitations so there is no need to connect any ports together. My guess is that the Pro 64 data sheet was an edited version of the Pro 40 data sheet and that the author didnt make the appropriate changes to "disconnect" (separate) the connected pins! So functions other than A/D may also be shown incorrectly for P0 to P31. Be carefull with the description of ports P0 to P31 on the data sheet. Some of the functionality shown for these ports is, in fact, only available on ports P34 to P52 on the Pro 64. P34 to P52 are the ports that are connected to other ports on the Pro 40 to fit within the modules physical limitation of only 40 pins.

For what its worth, my concerns with the programming protocol were unfounded, the circuitry associated with the RESET pin is not critical and, in fact, the chip will program without the "critical" diode in circuit! A simple RC pullup on RESET appears to be all that is required.

Again thanks,
Peter Strong

Thanks for pointing out the data sheet error. I'll pass it along to the editor.

As for the diode in the reset circuit, it is not required when you reset the chip from outside(eg are programming the chip). However on a power up with no external reset the diode and cap create a POR along with internal features of the H8 chip. Without the didode/cap circuit on the reset pin this internal POR will not function and sometimes the H8 will not properly startup. If you have an external POR, or can reset the chip via the serial port everytime it powers up then you don't need the didode,cap circuit, other wise you do need it or you will get random failures to start running on power up.

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Thanks, Nathan, for the heads up on the RESET diode. I figured it was there for a reason and it is in my circuit and prototype.

Peter Strong

I just noticed what I posted was not what I intended sorry for any confusion. I tried to delete but I cant find an edit selection. Here is what was intended.