PCMCIA socket for the nanoEngine board

Miguel Freitas
Updated Sep 30, 2002

First of all... Rant mode!

nanoEngine is a very well designed StrongArm based board. It includes a 200MHz processor, 32MB SDRAM, 16MB Flash and an Intel 10/100Mbps ethernet chipset at an incredibly small size.
That board was created by a small company called BrightStar Engineering. Be aware they have limited resources and many people have trouble getting support from them.
My case is probably an extreme: I've e-mailed them several times, filled the web support form, sent faxes and got no response. Neither the "sales" nor "support" department gave me any information. I found that the only way you can ever expect to contact them is by calling Stuart Adams (BSE president) directly.
Even after pondering about the lack of resources to offer proper support, any technology company shouldn't, IMHO, completely ignore electronics communications. At least a standard message explaining the situation would be fine, it doesn't take more than 30 seconds to write a two-lines reply! I would really recommend using nanoEngine on your products, however you should seriously think about the support issue.

What is this document about?

Although nanoEngine is such a good product it doesn't have an important feature for my project needs: data storage. Fortunately StrongArm processor gives to the experienced engineer most of the support for adding PCMCIA/Compact-Flash cards. This document is about how to do a simple (no buffers, no hot-swap, no 5v) socket for PCMCIA.


Anyone intending to implement such thing will get into trouble very soon. To start with, the provided nanoEngine development kit is a complete waste of time (and money). They ship an old Linux kernel with things they built (god only knows how) and no documentation at all.

The only thing that keeped me from going crazy was the amazing work from Larry Doolittle: at his site he maintains documentations and patches for building a system for nanoEngine using only the freely available software and utilities. Thanks Larry!

The engineer will then need technical documentation about PCMCIA standard and StrongArm processor. I greatly recommend buying the book "The PCMCIA Developer's Guide". I've made a local copy of StrongArm datasheet.

After patching Larry's kernel, filling the missing gaps like control pins assignment and designing a PCB board you will find out that it doesn't work. With your logic analyzer you will quickly find that somehow BrightStar engineer(s) seem to have forgotten to let addresses lines signals to pass through the nanoEngine CPLD when accessing PCMCIA cards.

If you reach this stage you would be stuck like me. Fortunately Larry sent me the email of a helpful guy called Russell Heibel (thanks Russ!), that had this same problem and after much investigation with BSE got an updated CPLD code to fix the nanobridge. It was surprise for him to find that BSE still ships the buggy nanoEngine cards.

Reprogramming nanoEngine's CPLD

nanoEngine features a Cypress CY37256VP256-100BBC for all the digital logic, our mission is to reprogram it. Assuming that you don't have access to the Cypress ISR you will need three things:

You must do the cable to match nanoEngine evaluation board JTAG connector (it doesn't look standard, although i'm no JTAG specialist). This is how you should connect the signals:

UltraISR nanoevb J5
VCC (4)
GND (2,10)

Then follow Cypress documentation for using the JEDEC file and everything should be fine.

PCMCIA socket wiring

PCMCIA signals are connected to the StrongArm in an almost straightforward way. In my application i did not need the PCMCIA fancy features (like dual power voltage and hot insertion capability) therefore i haven't implemented them. Please notice that because of that i can't claim my socket to be PCMCIA compliant, it just works. Also i'm not responsible if you fry your hardware by not using the appropriated buffers the spec demands.

StrongArm manual doesn't specify where you should connect CD1/CD2, RESET and READY lines. I arranged those as following general purpose processor pins:

PCMCIA signals GPIO lines direction to cpu
Socket 0: READY GPIO11 input
Socket 0: CD1/CD2 GPIO13 input
Socket 0: RESET GPIO15 output
Socket 1: READY GPIO12 input
Socket 1: CD1/CD2 GPIO14 input
Socket 1: RESET GPIO16 output

Now here is the complete PCMCIA wiring for the Socket 0. I don't use any external logic, so this is about the simpler interface you can make. In fact, it should be possible to use even less connections by shortening to ground some of the higher addresses lines (thus reducing the usable PCMCIA window). CompactFlash should differ only on pin numbers.

PCMCIA pin PCMCIA signal nanoEngine signal pull-up resistor
1 Ground GND
2 Data 3 AD3
3 Data 4 AD4
4 Data 5 AD5
5 Data 6 AD6
6 Data 7 AD7
7 CE1# nPCE1
8 Address 10 AD18
9 OE# nPOE
10 Address 11 AD19
11 Address 9 AD17
12 Address 8 AD16
13 Address 13 AD21
14 Address 14 AD22
15 WE# nPWE
17 Vcc VCC
18 Vpp1
19 Address 16 AD24
20 Address 15 AD23
21 Address 12 AD20
22 Address 7 A7
23 Address 6 A6
24 Address 5 A5
25 Address 4 A4
26 Address 3 A3
27 Address 2 A2
28 Address 1 A1
29 Address 0 A0
30 Data 0 AD0
31 Data 1 AD1
32 Data 2 AD2
34 Ground GND
35 Ground GND
36 CD1# GPIO13 47k
37 Data 11 AD11
38 Data 12 AD12
39 Data 13 AD13
40 Data 14 AD14
41 Data 15 AD15
42 CE2# nPCE2
43 VS1#
46 Address 17 AD25
47 Address 18 AD26
48 Address 19 AD27
49 Address 20 AD28
50 Address 21 AD29
51 Vcc VCC
52 Vpp2
53 Address 22 AD30
54 Address 23 AD31
55 Address 24 GND
56 Address 25 GND
57 VS2#
59 WAIT# nPWAIT 47k
62 BVD2
63 BVD1
64 Data 8 AD8
65 Data 9 AD9
66 Data 10 AD10
67 CD2#
68 Ground GND

Kernel support

While debugging PCMCIA and IDE subsystem on kernel i realized it is very well designed. Almost all stuff needed to support PCMCIA/CompactFlash interface is already there, one just need to provide very small hardware dependent functions.

The patch below is partially inspired on sources from BrightStar SDK and other SA1110 drivers. It has not yet being ported to the latest kernel of Larry's site, but that must only require simple changes.

PCMCIA patch against linux-2.4.9-ac10-rmk2-np1-lrd1

linux-2.4.9-ac10-rmk2-np1-lrd1 patch


This is all you should need for bringing your PCMCIA card alive. After that, i would recommend compiling some pcmcia-cs utilities like "dump_cis" in order to check your adapter (for your convenience here you can grab it statically linked). The PCMCIA kernel code is also full of places were you can printk useful information to debug problems (like bytes read from CIS space).

When designing your application remember that, unlike in PC architecture, you don't have to set any PCMCIA resources. Trying to do so may cause errors to the pcmcia-cs userspace tools.

Have fun! ;)

please send your spam to this email

powered by
Center for Telecommunications Studies of PUC-Rio
PUC-Rio (Brasil)