I am facing some embarrassing problems recently.
After some trouble-shooting, I found that: We have Board-A and Board-B. Board-A and Board-B communicate to each other with a UART TTL Level Communication. The communication cable is around 80cm long. During the communication, I got a lot of UART errors.
My mission is to build a more reliable communication between Board-A and Board-B; but not allowed to modify the hardware design and baud-rate.
To me, it is not wise to use a UART TTL Level Communication between two boards. However, I am being told that, it is very popular to us to use a UART TTL Level Communication between two boards.
I tried to find some articles/documentation to convince the involved people, that, they should not use a UART TTL Level Communication between two boards. But I can not find anything useful. What I could find is something like: The UART usually does not directly generate or receive the external signals used between different items of equipment.
My question is: Where can I find some convincing articles/documentation to convince the involved people? (This is to avoid the future problems.) If I am not allowed to modify the hardware design and baud-rate, what choices do I have to build a more reliable communication?
Per,
Many thanks for your detailed and well-organized guidelines. (I had already read this guidelines; but did not say "thanks".)
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NO. no ground, no shield.
They said that, Board-A and Board-B get their power from the same power source. So an extra ground pin is unnecessary.
Board-A and Board-B are assembled into the customer's end-product in the customer's factory. So the real cable is manufactured by the customer. They said, the real cable is similar to the cable I use; no ground, no shield. If this information is correct, then our customer does not see the need of an extra ground pin either.
If it is true that, both our customer and we don't see the need of ground pins, well, then this is a problem to the local industry.
The problems of Board-B were raised again yesterday. Two or three persons will be sent to the customer side to do the troubleshooting/explanation on next Monday, One to Mainland China, one to northern Taiwan.
I have a feeling that, many engineers here do their work to destroy their companies and their customers, busy in producing terrible hardware and software, busy in endless troubleshooting.
I am in charge to develop a new product which integrates the functionality of Board-A and Board-B. It seems that they prefer to use the hardware of Board-B for the new product. So the MCU would be Fujitsu MB90350, which is a MCU first-time released to the market on 2003. How wonderful and amazing.
People were talking about ISO-26262 here. And I noticed that TI announced some new MCUs recently, the ARM Cortex based, Hercules RM4x/TMS570/TMS470M, which have some kind of hardware support for ISO-26262. But all of these are just adornments to us; because our products are already solid enough.