The LCDuino-1 I/O processor

[amb]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif neither of those 2. what you want (what I recommend, at least) is the ftdi 6pin usb/serial cable, such as this one: USB TTL-232 cable [TTL-232R 3.3V] - $20.00 : Adafruit Industries, Unique & fun DIY electronics and kits mouser also carries it but people often order the wrong one ;( adafruit only carries 1 type of ftdi cable so that's the easier order, imho.

Actually, Mouser, Digi-Key, Farnell and RS Components all have it:

Mouser 895-TTL-232R-3V3
Digi-key 768-1015-ND
Farnell 1329311
RS 429-307

These are links to the correct one with the 6P SIP receptacle. The official FTDI part number is "TTL-232R-3V3", but if you search on that, you'll also find other variants (additional suffix on the part number, with different connectors or bare wires). Most arduino folks use the linked one with no additional suffix. Here is the datasheet for the cable and its variants:

http://www.ftdichip.com/Documents/Da...ABLES_V201.pdf

 

[glt]

Here is a $3 option: Arduino Forum - Using a cell phone cable as a cheap ($3) USB TTL

 

[linuxworks]

in fact, I tried to locate some of those cheap phone cables

I did find a usb-serial cable that uses the prolific brand chipset; but the chip is buried in thick molded plastic and you have to cut it away to bypass the level converter. too much effort given that the cable is $10 and I'd put way more than $10 of effort into it and still not get the ftdi chip, itself.

also, you'd want to have the auto-reset feature if at all possible and not all cellphone cables have the line needed for that.

it was a neat idea but too hacky for me, personally. the $20 cable is a one-time purchase and that's quite cheap as far as development environments go.

my first controller was a BASIC stamp (bs1) and that chip, just by itself, was way more than the $20 I paid for the arduino ftdi cable

 

[stwspoon]

I have had good luck with the Modern Device USB BUB Board USB to TTL serial board for $12 and you can configure it for 5V or 3.3V. For an additional $1.50 they throw in a 3' A to Mini B cable. It is all assembled except for the connector so that you can customize it. The std pinout is the same as the FTDI cable for the Arduino.

Not affiliated, just a satisfied customer.

I can't wait to get my hands on a LCDuino. When is the next round of boards scheduled?

 

[amb]

Quote:

Originally Posted by stwspoon /img/forum/go_quote.gif I can't wait to get my hands on a LCDuino. When is the next round of boards scheduled?

Unknown. I might order more prototype boards if there is a good reason for it, but at the moment I am waiting for the existing prototype team to really get rolling, so I could incorporate all feedback and changes for the eventual production board.

 

[luvdunhill]

Thanks everyone for the suggestions. Goodies have been ordered.

One more thing I'm looking for is a cheap way to program SOIC microcontrollers. I figure I could clamp them to a protoboard or something, but I remember seeing some nice ZIF sockets that PIC programmers use for this back in the day... any recommendations for this type of gadget?

 

[stwspoon]

I have used a SOIC chip clip in the past. something like this though the sockets are much nicer but also $$. If you only have a few the clip may do it. If you have not ordered the chips yet, some companies will program them for you.

 

[luvdunhill]

That looks nice, but doesn't that require the device to be soldered? Can you use it "free air"? As for the pre-programming, who offers that sort of service in small quantities?

 

[stwspoon]

I have had reasonable luck in putting the SOIC down on an antistatic surface and clipping the clip down over the SOIC. The clip grabs the SOIC body and contacts the leads as they come out of the body and bend down. You just have to be prepared for the SOIC to go flying off somewhere if you don't get the clip on right

. Digikey and Arrow electronics will program chips ordered from them, according to this PicList thread. At the bottom of the thread is someone offering programming services. Other threads indicate that Microchip Direct offers a programming service. A ZIF SOIC socket is about $140

at Digikey.

 

[linuxworks]

some devel news: today I have the PGA volume control chip (pga23xx series) working across i2c via a port expander chip. I'm using a phliips PCFxxx series chip (for variety) and can remotely send {chipselect, clock, data} over i2c via a 'bit bang' at the i2c message level

ie, for each of the 16 bits that are needed (8 for left, 8 for right) you send the (cs, clock, data) but toggle clock and cycle around the data bit until done with all 16.

so far, it seems to work. this offloads 3 'valuable' digital i/o pins from the arduino cpu, itself, and allows the volume control system to be truly an i2c slave device on the i2c bus. less wiring to the main lcduino board, too

I've been using i2c to control a relay attenuator bank but this is the first time I've used i2c to control the burr brown PGA chip via this bridged big-bang method. I also modified my SPDiFmaster so that it, also uses a port expander over i2c and selects the input spdif port via a 2bit binary enum that is simply sent to the 'well known' spdif selector i2c address.

so far, the idea of 'putting everything non-analog on i2c' seems to be working. of course the motorized linear-taper pot can't come in via a PE, it has to 'burn' a true analog-in port on the lcduino. the rotate control bits, though (move_left and move_right) could be on 2 unused PE bits somewhere.

 

[linuxworks]

2 more updates and a question:

update1: new feature 'IR key aliasing'. the beta code now allows you to define more than 1 IR key code for any given internal function. suppose you have 2 nice handheld remotes that you like and use often and maybe they both have vol up/down buttons. it would be nice if EITHER of those 2 remotes would trigger the same 'vol up' function in VoluMaster, for example. and that's what I did: created a way to allow extra keys (from the same or different remote, even different brand and protocol) to map to the same internal function. my use-case was wanting to be able to use the vol up/down keys on my slimdevices squeezebox remote and have them actually control my PGA vol control chip. the native vol control on the slimdevices box is disabled in spdif-out so it works just fine with no overlap.

update2: half-db steps on up/down are now allowed. you can set a global mode with an IR key to switch to half-db mode or full-db mode. all volume adjustments increment or decrement by the right db amount and the display changes to show "42.5" instead of "42dB", when in half-db mode. the volume range now goes 0..255 instead of 0..127 as it did before, using all 8 bits. when in full-db mode, volume is bumped up 2 counts each time, so that the 0..255 range is still maintained.

and now the question: does anyone have any recommendation on a 4 pin *very small* keyed (polarized) connector? what I'm looking for is something to carry i2c signals, which are {clock, data, vcc, gnd}. I wonder if there are things like the mini-usb connectors but with .1 spacing so that they work out on perf and pc boards? something about the size of mini-usb, too; but I also need easy ways to make cables and mini-usb is not very user-friendly when it comes to making your own headers and jumpers.

does anyone have any good ideas for small molex (?) keyed 4 pin connectors (headers and plugs) for this application? I think a lot of 'application boards' will have an i2c input and i2c passthru points on it and so I can see a lot of use for chaining i2c functions and needing a connector/plug/socket standard.

 

[luvdunhill]

Quote:

Originally Posted by linuxworks /img/forum/go_quote.gif and now the question: does anyone have any recommendation on a 4 pin *very small* keyed (polarized) connector?

cat5?

 

[m1abrams]

Why not just a 4 pin KK molex? .1 spacing, cheap, pretty easy to work with even without the crimp tool. Any smaller than that and it becomes a pain to make cables IMHO.

 

[m1abrams]

Just saw the cat5 suggestion, that is not a bad idea either. However if it is meant for just inter-board connections and not intercase I think it would be a little bulky.

 

[linuxworks]

Quote:

Originally Posted by m1abrams /img/forum/go_quote.gif Why not just a 4 pin KK molex? .1 spacing, cheap, pretty easy to work with even without the crimp tool. Any smaller than that and it becomes a pain to make cables IMHO.

those are inline, which takes up more room than I was hoping for. they are keyed (good) and easy/cheap (good) but I was imagining something line 4 pins in a 2x2 layout with some index key or shape key somewhere.

but a 4pin KK is a good standby to have if nothing else becomes the obvious choice.