Lpc2000

Hi,

I am trying to attach an external device to the data and address bus of 
the LPC2214. With a logic analyzer I can see that all of the signal 
lines for the external bus are correct except the WE (write enable) 
signal. The correct values are presented on the data and address bus. 
The CS0 signal and the BLS0 signal go low at the correct time, but the 
WE signal stays high for the entire write cycle. Bit 8 of the PINSEL2 
register has been set high, so the WE function should be selected for 
the pin. The WE pin is only connected to an input pin of a NAND gate 
and an input pin of the external device. The external device is a 
NET2272 USB chip. Is there something that I am missing? Can anyone 
suggest what I am doing wrong? I could not find and errata document for 
the LPC2214 on the Philips site. Can someone point me to the errata doc 
for the LPC2214?

Thanks,
Bob Davis

Try setting RBLE BIT(10) in the BCFGn register.  Contrary to the docs,
I found this necessary even for non-byte-partitioned, 16-bit devices.
Also make sure that WP BIT(26) is clear.

Good luck
-Bill Knight
R O SoftWare &
http://www.theARMPatch.com


On Wed, 27 Apr 2005 20:54:24 -0000, rkdwork wrote:

Hi,

I am trying to attach an external device to the data and address bus of 
the LPC2214. With a logic analyzer I can see that all of the signal 
lines for the external bus are correct except the WE (write enable) 
signal. The correct values are presented on the data and address bus. 
The CS0 signal and the BLS0 signal go low at the correct time, but the 
WE signal stays high for the entire write cycle. Bit 8 of the PINSEL2 
register has been set high, so the WE function should be selected for 
the pin. The WE pin is only connected to an input pin of a NAND gate 
and an input pin of the external device. The external device is a 
NET2272 USB chip. Is there something that I am missing? Can anyone 
suggest what I am doing wrong? I could not find and errata document for 
the LPC2214 on the Philips site. Can someone point me to the errata doc 
for the LPC2214?

Thanks,
Bob Davis

Bob, 
Could it be that you are using 8 bits databus interface? If so the WE
signal is not used - It is frozen high. You have to use the BLS0 signal
as WE! Take a look at the "Figure 9: 8 Bit Bank External Memory
Interface" in the user manual for LPC2214.

Sveinung

-----Original Message-----
From: lpc2000@yahoogroups.com [mailto:lpc2000@yahoogroups.com] On Behalf
Of rkdwork
Sent: 27. april 2005 22:54
To: lpc2000@yahoogroups.com
Subject: [lpc2000] Problem with WE signal on LPC2214



Hi,

I am trying to attach an external device to the data and address bus of 
the LPC2214. With a logic analyzer I can see that all of the signal 
lines for the external bus are correct except the WE (write enable) 
signal. The correct values are presented on the data and address bus. 
The CS0 signal and the BLS0 signal go low at the correct time, but the 
WE signal stays high for the entire write cycle. Bit 8 of the PINSEL2 
register has been set high, so the WE function should be selected for 
the pin. The WE pin is only connected to an input pin of a NAND gate 
and an input pin of the external device. The external device is a 
NET2272 USB chip. Is there something that I am missing? Can anyone 
suggest what I am doing wrong? I could not find and errata document for 
the LPC2214 on the Philips site. Can someone point me to the errata doc 
for the LPC2214?

Thanks,
Bob Davis 





 
Yahoo! Groups Links

Thank you Bill and Sveinung for your replies. It is great to have 
people to turn to with a problem. I followed Bill's suggestion and set 
RBLE in the BCFG0 register to 1. Now WE works as expected and I can 
read from and write to the NET2272. Thanks again. You saved me a lot of 
time.

Bob Davis