StephenFromNYC
Moderator
Hello,
I have a question about pin D3 on the Maple Rev 3 (summer 2010) board.
Can the D3 pin be used for analog (ADC) input?
I am asking, because web site page ("Maple Docs: ADC"):
http://leaflabs.com/docs/maple/adc/
includes D3, but the letters AIN are not silkscreened on my board.
Also, on the back of the board, a black marker was used to cover pin "38' on the silkscreen. What does this indicate?
Thanks!
StephenFromNYC
Moderator
Hello,
More comments regarding my previous post (above).
1) Analog Input and Maple Pin D3
In the table of the web site ("Maple Docs: GPIO"):
http://leaflabs.com/docs/maple/gpio/
It says D3 is ADC1 (and is connected to STM32 Pin PA1). I have not checked the STM documentation yet so I do not know what to conclude.
2) Pin "38" marking
I now understand why the "38" on the back of the Maple Rev 3 card is covered using a black marker.
Pin 38 is the BUT on the card. The last pin on the double-row plastic "riser" is ground GND.
If this is true then the "38" on the front of the Rev 3 card should also be marked out before the double-row plastic "riser" is soldered.
I hope these conclusions are correct.
Thanks!
Stephen from NYC
leaflabsandy
Member
The new rev. 5 Maple, which supersedes the rev. 3 Maple, is being re-done and I believe
the silkscreen is being fixed plus some other changes.
Link: http://forums.leaflabs.com/topic.php?id=103
On a further note... there is even a silkscreen on the bottom of the board? I am still trying to figure its use out because, in my case, the board is securely fastened via mounting holes to an enclosure. Maybe I need a mirror?
gbulmer
Moderator
Stephen
I checked the Maple Eagle CAD, and yes, D3 is conected to
PA1/USART2_RTS/ADC12_IN1/TIM2_CH2 on the STM32F physical pin P$15.
The Maple library currently only uses 1 ADC to read values, so ADC12_IN1 would be read using ADC1 on channel 1.
I checked wirish_analog.c, which contains analogRead(uint8 pin), which in turn uses a lower level function adc_read(int channel) (in adc.h) and the adc channel field in an array of struct's called PIN_MAP[].
So analogRead takes a pin number, and converts it into the adc channel using PIN_MAP[pin].adc
so just do analogRead(3), and it "should Just Work" (TM)
StephenFromNYC
Moderator
Hello,
For those who have fastened their Maple Rev 3 (summer 2010) boards into enclosures. This is what I see printed on the bottom of the board:
<start of info>
5: I2C1-SCL
9: I2C1-SDA
10: SPI1 ss (nss)
11: SPI1 mosi
12: SPI1 miso
13: SPI1 ck
GND (between 13 and 14)
24: PWM
27: PWM/AIN
28: PWM/AIN
29: TX3/I2C2-SCL
30: RX3/I2C2-SDA
31: SPI2-NSS
32: SPI2-SCK
33: SPI2-MISO
34: SPI2-MOSI
GND
<end of info>
This seems consistent with the info on "Maple Docs GPIO":
http://leaflabs.com/docs/maple/gpio/
However, there is more information on the web site. For example pins D32 and D33 are also also used by Serial3 for Clear to Send and Ready to Send (USART3_CTS and USART3_RTS).
I have not used JTAG before. On the top of the board the eight JTAG hole number assignments are clear. However, on the bottom of the card the five hole numbers are 39, 40, 41, 42, and 43 seem to be assigned haphazardly. If I am viewing them correctly they correspond as follows:
JTAG (top): 1 = 43 (bottom)
JTAG (top): 3 = 40 (bottom)
JTAG (top): 4 = 42 (bottom)
JTAG (top): 5 = 41 (bottom)
JTAG (top): 6 = 39 (bottom)
Hope this is helpful.
Thanks!
Stephen from NYC
StephenFromNYC
Moderator
Hello,
I reinvented the wheel again.
The leaflabs site has a simple PNG file of the maple rev 3 board:
http://static.leaflabs.com/pub/leaflabs/maple-hardware/rev3/maple-rev3-layout-bottom.png
This image shows the silk-screened text, but from the perspective of the top of the board. To be more legible just use a graphic app and flip the image.
Thanks!
Stephen from NYC
You must log in to post.
