[Gta04-owner] Error in pin layout of serial cable?

Dr. H. Nikolaus Schaller hns at goldelico.com
Mon Dec 5 14:46:54 CET 2011


Hi,

Am 05.12.2011 um 01:30 schrieb Jens Seidel:

> Hi,
> 
> I received my new board a few days ago and think I found an error in
> the pin location of the serial cable. Pins 7 and 8 have to be swapped
> in the table in the manual (so that this matches the picture of the
> cable adapter at page 36):
> 
> According to page 35 of the PDF manual
> http://projects.goldelico.com/p/gta04-main/downloads/37/:
> 
> "Pin location and signals:
> 
> Pin DCE pin UART3 GPIO Dir. Color (in our presoldered cable) DB9f pin
> name (mode0) (mode4) number
> 1 GND - - - brown 5
> 2 EXT - 21 Out red 1 (DCD)
>                  4 (DTR)
>                 9 (RI)
> 3 CTS RTS 164 Out orange 7
> 4 TX RX 166 In yellow 3
> 5 RTS CTS 163 In green 8
> 6 RX TX 165 Out blue 2
> 7 GND - - - purple -
> 8 DCIN - - In grey -
> "
> 
> 7, 8 = orange, green = CTS, RTS
> 
> This seems to contradict with e.g.
> http://www.interfacebus.com/Design_Connector_RS232.html:
> 
> RS232 DB-9 Connector Pin Out Pin # 	Signal Name 	Signal Description
> 1 	CD 	Carrier Detect
> 2 	RXD 	Receive Data
> 3 	TXD 	Transmit Data
> 4 	DTR 	Data Terminal Ready
> 5 	GND 	Signal Ground / Common
> 6 	DSR 	Data Set Ready
> 7 	RTS 	Request To Send
> 8 	CTS 	Clear To Send
> 9 	RI 	Ring Indicator

I will double check it. It is an area that is attracting 
and pulling you into the swamp of mistakes...

The RS232 cable is configured and named as
a DCE (i.e. Modem) so that it does not need
a Null-Modem when being connected to a DTE.

> 
> With the fixed layout I did not yet receive any output but maybe I did
> something wrong :-)
> The display backlight is on (it doesn't turn off for a short time),

This means that the MLO does not start from SD card (it turns
it off for a moment and U-Boot turns it on again). Or did you use
the "new" 512MB MLO? I don't know if it has this "feature".

> now I disconnected it again. No change.
> 
> Found also some minor issues in the makesd script, which I will report
> separately. Maybe my sd card doesn't contain a bootable system.

The most important thing is that the MLO is the first file on the FAT
partiton.

Anyways you should be able to see the "60" on the RS232.

> 
> A remark to the replacing instruction (page 24):
> "4.5. Glueing the Touch&LCD module onto the GTA04 PCB
> 1. Peel off the plastic cover on the double-sided tape of the GTA04 PCB."
> 
> Huh? Is there a double-sided tape on the new motherboard? I haven't

Maybe we forgot on your board. There should have been a double-sided
"Tesa Bastelband" on the PCB.

> seen it and glued the display with double-sided transparent tesa
> strip. Probably not the best solution but did I miss something?

Yes, this is ok. Unless you peel off the strips rapidly with high force.
This may create electricity./ ESD.


More information about the Gta04-owner mailing list