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Maple Native β

This page is a general resource for information specific to the Maple Native Beta. Since this is a beta release, the information here may change slightly between now and the final Maple Native release.

Technical Specifications

  • MCU: STM32F103ZET6 <maple-native-b-stdocs>, a 32-bit ARM Cortex M3 microprocessor.
  • Clock Speed: 72 MHz
  • 512 KB Flash, 64 KB SRAM (on-chip), 1 MB SRAM (external)
  • 106 digital I/O pins
  • 17 PWM pins at 16 bit resolution
  • 21 analog input (ADC) pins at 12-bit resolution
  • 3 SPI peripherals
  • 2 I2C peripherals
  • 12 Channels of Direct Memory Access (DMA) (dma.h) with 2 DMA controllers
  • 3 USART (serial port) peripherals, 2 UART peripherals
  • 2 advanced, 4 general-purpose, and 2 basic timers
  • Dedicated USB port for programming and communications
  • JTAG
  • Nested Vectored Interrupt Controller (NVIC) (including external interrupt on GPIOs)
  • Supplies up to 500 mA at 3.3 V, with separate 250 mA digital and analog regulators for low-noise analog performance
  • Open-source, four layer design
  • Support for low power, sleep, and standby modes (<500 μA)
  • Operating Voltage: 3.3 V
  • Input Voltage (recommended): 3 V — 12 V
  • Dimensions: 4″ × 2.1″

Powering the Maple Native

The power source is determined by the header labeled “PWRSEL” on the silkscreen. The Maple Native may be powered from USB (marked “USB” on the PWRSEL header), a LiPo battery (marked “BAT”), or one of the two “Vin” pins (marked “EXT”). Boards are shipped with a jumper on the USB selector. In order to power it off of an alternative source, unplug the Maple Native, then move the jumper to the desired selector before reconnecting power.

The “Vin” line is available on the pin labeled “Vin” on the vertical header to the right of the PWRSEL header, as well as on the unpopulated two-pin connector on the upper left corner of the board. On this latter connector, polarity was accidentally left unmarked: the leftmost, round pin should be power, while the square pin should be ground.

When powering the Maple Native board from a battery or the Vin lines, care must be taken not to over-voltage the board. In general, an upper limit of 12V input is acceptable, but this may vary depending upon the current draw requirements of the application. Please see Power Regulation on the Maple Native for more information.

Power Regulation on the Maple Native

Power regulation on the Maple Native is provided by two low dropout linear voltage regulators. (The part is the MCP1703 from Microchip, in the SOT-23A package. You can download the datasheet here). One of the regulators supplies power to the digital voltage plane; the other supplies power to the analog voltage plane.

These voltage regulators nominally take an input of up to 16V. In addition, while the maximum continuous output current for the board is 250mA, if you are powering the board off higher voltages the amount off current it can supply goes down, due to the regulators needing to dissipate the extra power. So if you are powering the board off 12V, the max current is about 40mA at room temperature. In general (again, at room temperature) the max power dissipation (PD) for the chip is about .37W, and output current = PD/(Vin-Vout). For exact max current calculations, please refer to the datasheet linked above.

If you are planning to draw a lot of current from the Maple Native board, it is necessary to provide input power as close to 3.3V as possible. Powering the microcontroller circuitry and LEDs on the board alone takes approximately 30mA, so if you are powering the board with 12V that leaves only 10mA (at best) available for powering any user circuitry. Attempting to draw more than 10mA runs the risk of shorting out the power regulators and bricking your board.

Using the Built-in Battery Charger

Maple Native includes a built-in LiPo battery charger. In order to use it, put a jumper across the CHRG selector on the PWRSEL header and across the USB, or EXT selectors, depending on whether you’re charging the battery via USB cable or Vin, respectively. The LED labeled CHRG will light up while the battery is being charged. When the battery is finished charging, the LED labeled DONE will light up.

GPIO Information

The Maple Native features 106 total input/output pins, numbered D0 through D105. In most cases, these numbers correspond to the numeric values next to each header on the Maple Native’s silkscreen. However, pins D101 through D105 are broken out to the JTAG header, and are not numbered on the silkscreen. In addition, some other pins have other uses by default [1].

Pin D6 is the Native’s button pin. It is thus mainly useful as an input. The pin will read HIGH when the button is pressed.

Pin D22 is the Native’s LED pin. It is thus mainly useful as an output. The LED will glow when HIGH is written to it.

Many of the pins on the right header (pins D56 through D100, the header is labeled “FSMC” on the silkscreen) are connected to the SRAM chip. Using these pins as GPIOs may render the memory chip useless, which can cause your program to crash. For this reason, we don’t recommend that you use these pins unless you know what you are doing. The following pins on the right header are not connected to the SRAM and may be used with impunity: D57, D60, D63, D66, D69, D72, D75, D80, D83.

Pins D101 through D105 are connected to the pads on the JTAG header. In order to use them as GPIOs, you must first disable the Maple Native’s debug ports. You can do this by calling disableDebugPorts(). (Note that this means you won’t be able to use JTAG or SW-Debug to debug your program).

Master Pin Map

This table shows a summary the available functionality on every GPIO pin, by peripheral type. The “5 V?” column documents whether or not the pin is 5 volt tolerant.

Note that this table is not exhaustive; on some pins, more peripherals are available than are listed here.

Top header:

Pin GPIO ADC Timer I2C UART SPI 5 V?
D0 PB10
2_SCL 3_TX
Yes
D1 PB11
2_SDA 3_RX
Yes
D2 PB12
1_BKIN 2_SMBA 3_CK 2_NSS Yes
D3 PB13
3_CTS 2_SCK Yes
D4 PB14
3_RTS 2_MISO Yes
D5 PB15
2_MOSI Yes
D6 PG15
Yes
D7 PC0 1_CH10
D8 PC1 1_CH11
D9 PC2 1_CH12
D10 PC3 1_CH13
D11 PC4 1_CH14
D12 PC5 1_CH15
D13 PC6
8_CH1
Yes
D14 PC7
8_CH2
Yes
D15 PC8
8_CH3
Yes
D16 PC9
8_CH4
Yes
D17 PC10
4_TX
Yes
D18 PC11
4_RX
Yes
D19 PC12
5_TX
Yes
D20 PC13
D21 PC14
D22 PC15
D23 PA8
1_CH1
1_CK
Yes
D24 PA9
1_CH2
1_TX
Yes
D25 PA10
1_CH3
1_RX
Yes
D26 PB9
4_CH4
Yes

Bottom header:

Note

D48, D49, D50, D51 are also connected to Timer 2 channels 1, 2, 3, and 4, respectively.

Pin GPIO ADC Timer I2C UART SPI 5 V?
D27 PD2
3_ETR
5_RX
Yes
D28 PD3
Yes
D29 PD6
Yes
D30 PG11
Yes
D31 PG12
Yes
D32 PG13
Yes
D33 PG14
Yes
D34 PG8
Yes
D35 PG7
Yes
D36 PG6
Yes
D37 PB5
1_SMBA
3_MOSI
D38 PB6
4_CH1 1_SCL
Yes
D39 PB7
4_CH2 1_SDA
Yes
D40 PF11
Yes
D41 PF6 3_CH4
D42 PF7 3_CH5
D43 PF8 3_CH6
D44 PF9 3_CH7
D45 PF10 3_CH8
D46 PB1 1_CH9 3_CH4
D47 PB0 1_CH8 3_CH3
D48 PA0 1_CH0 5_CH1
2_CTS
D49 PA1 1_CH1 5_CH2
2_RTS
D50 PA2 1_CH2 5_CH3
2_TX
D51 PA3 1_CH3 5_CH4
2_RX
D52 PA4 1_CH4
2_CK 1_NSS
D53 PA5 1_CH5
1_SCK
D54 PA6 1_CH6 3_CH1
1_MISO
D55 PA7 1_CH7 3_CH2
1_MOSI

Right (FSMC) header

All of the following pins are 5V-tolerant. Note that in the “FSMC” column below, entries with a “Dn” value (D0, D1, etc.) don’t refer to pins; they refer to FSMC data lines. See RM0008 for more information.

Warning

Many of the pins on this header are used by the Maple Native’s SRAM chip. Don’t use them as GPIOs unless you know what you’re doing, or your program may crash. See above for more information.

Pin GPIO FSMC
D56 PF0 A0
D57 PD11 A16
D58 P14 D0
D59 PF1 A1
D60 PD12 A17
D61 PD15 D1
D62 PF2 A2
D63 PD13 A18
D64 PD0 D2
D65 PF3 A3
D66 PE3 A19
D67 PD1 D3
D68 PF4 A4
D69 PE4 A20
D70 PE7 D4
D71 PF5 A5
D72 PE5 A21
D73 PE8 D8
D74 PF12 A6
D75 PE6 A22
D76 PE9 D6
D77 PF13 A7
D78 PE10 D7
D79 PF14 A8
D80 PG9 NE2/NCE3
D81 PE11 D8
D82 PF15 A9
D83 PG10 NCE4_1/NE3/NCE4_2
D84 PE12 D9
D85 PG0 A10
D86 PD5 NWE
D87 PE13 D10
D88 PG1 A11
D89 PD4 NOE
D90 PE14 D11
D91 PG2 A12
D92 PE1 NBL1
D93 PE15 D12
D94 PG3 A13
D95 PE0 NBL0
D96 PD8 D13
D97 PG4 A14
D98 PD9 D14
D99 PG5 A15
D100 PD10 D15

JTAG header pins

Note

See above for more information on these pins.

Pin GPIO SPI 5 V?
D101 PA13
Yes
D102 PA14
Yes
D103 PA15 3_NSS Yes
D104 PB3 3_SCK Yes
D105 PB4 3_MISO Yes

GPIO Port Pin Map

The following tables show what pins are associated with each GPIO port.

GPIOA GPIOB GPIOC GPIOD
PA0: D48 PB0: D47 PC0: D7 PD0: D64
PA1: D49 PB1: D46 PC1: D8 PD1: D67
PA2: D50 PB2: - PC2: D9 PD2: D27
PA3: D51 PB3: D104 PC3: D10 PD3: D28
PA4: D52 PB4: D105 PC4: D11 PD4: D89
PA5: D53 PB5: D37 PC5: D12 PD5: D86
PA6: D54 PB6: D38 PC6: D13 PD6: D29
PA7: D55 PB7: D39 PC7: D14 PD7: -
PA8: D23 PB8: - PC8: D15 PD8: D96
PA9: D24 PB9: D26 PC9: D16 PD9: D98
PA10: D25 PB10: D0 PC10: D17 PD10: D100
PA11: - PB11: D1 PC11: D18 PD11: D57
PA12: - PB12: D2 PC12: D19 PD12: D60
PA13: D101 PB13: D3 PC13: D20 PD13: D63
PA14: D102 PB14: D4 PC14: D21 PD14: D58
GPIOE GPIOF GPIOG
PE0: D95 PF0: D56 PG0: D85
PE1: D92 PF1: D59 PG1: D88
PE2: - PF2: D62 PG2: D91  
PE3: D66 PF3: D65 PG3: D94
PE4: D69 PF4: D68 PG4: D97
PE5: D72 PF5: D71 PG5: D99
PE6: D75 PF6: D41 PG6: D36
PE7: D70 PF7: D42 PG7: D35
PE8: D73 PF8: D43 PG8: D34
PE9: D76 PF9: D44 PG9: D80
PE10: D78 PF10: D45 PG10: D83
PE11: D81 PF11: D40 PG11: D30
PE12: D84 PF12: D74 PG12: D31
PE13: D87 PF13: D77 PG13: D32
PE14: D90 PF14: D79 PG14: D33

Timer Pin Map

The following table shows what pins are associated with a particular timer’s capture/compare channels.

There is no mistake between timers 2 and 5. They really do share those pins. If you like, you can remap some of the timer 2 channels to get extra PWM pins; see afio_remap() (in gpio.h).

Timer Ch. 1 Ch. 2 Ch. 3 Ch. 4
1 D23 D24 D25  
2 D48 D49 D50 D51
3 D54 D55 D47 D46
4 D38 D39   D26
5 D48 D49 D50 D51
8 D13 D14 D15 D16

EXTI Line Pin Map

The following table shows which pins connect to which EXTI lines.

EXTI Line Pins
EXTI0 D7, D47, D48, D56, D64, D85, D95
EXTI1 D8, D46, D49, D59, D67, D88, D92
EXTI2 D9, D27, D50, D62, D91
EXTI3 D10, D28, D51, D65, D66, D94, D104
EXTI4 D11, D52, D68, D69, D89, D97, D105
EXTI5 D12, D37, D53, D71, D72, D86, D99
EXTI6 D13, D29, D36, D38, D41, D54, D75
EXTI7 D14, D35, D39, D42, D55, D70
EXTI8 D15, D23, D34, D43, D73, D96
EXTI9 D16, D24, D26, D44, D76, D80, D98
EXTI10 D0, D17, D25, D45, D78, D83, D100
EXTI11 D1, D18, D30, D40, D57, D81
EXTI12 D2, D19, D31, D60, D74, D84
EXTI13 D3, D20, D32, D63, D77, D87, D101
EXTI14 D4, D21, D33, D58, D79, D90, D102
EXTI15 D5, D6, D22, D61, D82, D93, D103

USART Pin Map

The Maple Native has 3 USART serial ports. They communicate using the pins given in the following table.

Serial port TX RX CK CTS RTS
Serial1 D24 D25 D23    
Serial2 D50 D51 D52 D48 D49
Serial3 D0 D1 D2 D3 D4

The Maple Native also has 2 UART serial ports. Unlike USARTS, these only communicate asynchronously, and thus only have TX and RX pins. These are given in the following table.

Serial port TX RX
Serial4 D17 D18
Serial5 D19 D27

Low-Noise ADC Pins

There are fifteen pins at the bottom right of the board (D41 — D55) that generally offer lower-noise ADC performance than other pins on the board. If you’re concerned about getting good ADC readings, we recommend using one of these pins to take your measurements.

Maple Native has an electrically isolated analog power plane with its own regulator, and a geometrically isolated ground plane. Analog input pins D41 — D55 are laid out to correspond with these analog planes, and our measurements indicate that they generally ofer low noise ADC performance. However, analog performance may vary depending upon the activity of other GPIOs. In particular, using PWM on any of pins D46 — D51, D54, and D55 may cause digital noise. Consult the Maple Native beta hardware design files for more details.

Board-Specific Values

This section lists the Maple Native’s board-specific values.

  • CYCLES_PER_MICROSECOND: 72

  • BOARD_BUTTON_PIN: 6

  • BOARD_LED_PIN: 22

  • BOARD_NR_GPIO_PINS: 106

  • BOARD_NR_PWM_PINS: 18

  • boardPWMPins: 13, 14, 15, 16, 23, 24, 25, 26, 38, 39, 46, 47, 48, 49, 50, 51, 54, 55

  • BOARD_NR_ADC_PINS: 21

  • boardADCPins: 7, 8, 9, 10, 11, 12, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55

  • BOARD_NR_USED_PINS: 43

  • boardUsedPins: BOARD_LED_PIN, BOARD_BUTTON_PIN,

    BOARD_JTMS_SWDIO_PIN, BOARD_JTCK_SWCLK_PIN, BOARD_JTDI_PIN, BOARD_JTDO_PIN, BOARD_NJTRST_PIN, and all pins on FSMC header except those mentioned above.

  • BOARD_NR_USARTS: 5

  • BOARD_USART1_TX_PIN: 24

  • BOARD_USART1_RX_PIN: 25

  • BOARD_USART2_TX_PIN: 50

  • BOARD_USART2_RX_PIN: 51

  • BOARD_USART3_TX_PIN: 0

  • BOARD_USART3_RX_PIN: 1

  • BOARD_UART4_TX_PIN: 17

  • BOARD_UART4_RX_PIN: 18

  • BOARD_UART5_TX_PIN: 19

  • BOARD_UART5_RX_PIN: 27

  • BOARD_NR_SPI: 3

  • BOARD_SPI1_NSS_PIN: 52

  • BOARD_SPI1_MOSI_PIN: 55

  • BOARD_SPI1_MISO_PIN: 54

  • BOARD_SPI1_SCK_PIN: 53

  • BOARD_SPI2_NSS_PIN: 2

  • BOARD_SPI2_MOSI_PIN: 5

  • BOARD_SPI2_MISO_PIN: 4

  • BOARD_SPI2_SCK_PIN: 3

  • BOARD_SPI3_NSS_PIN: 103 (on JTAG header)

  • BOARD_SPI3_MOSI_PIN: 37

  • BOARD_SPI3_MISO_PIN: 105 (JTAG header)

  • BOARD_SPI3_SCK_PIN: 104 (JTAG header)

  • BOARD_JTMS_SWDIO_PIN: 103

  • BOARD_JTCK_SWCLK_PIN: 102

  • BOARD_JTDI_PIN: 103

  • BOARD_JTDO_PIN: 104

  • BOARD_NJTRST_PIN: 105

Hardware Design Files

The hardware schematics and board layout files are available in the Maple Native GitHub repository. Download the beta version’s hardware design files (ZIP format).

If you’re familiar with Git, you can clone the entire repository and checkout the commit tagged “beta” using the following:

$ git clone git://github.com/leaflabs/maplenative.git
$ git checkout beta

Failure Modes

The following known failure modes apply to the Maple Native Beta. The failure modes aren’t design errors, but are easy ways to break or damage your board permanently.

  • Reversing Vin and GND: when powering the Maple Native Beta via the Vin and ground (GND) pins at the top left of the board, it is possible to carelessly cause a short or switch the connections, applying the high voltage to GND and ground to Vin.

    If this happens, you will reverse bias the diode beneath these pins, most likely damaging it. This may cause excess voltage to subsequently be delivered to the board once the reversed pins are connected properly.

Errata

This section lists known issues and warnings for the Maple Native Beta.

  • PWM on pin 39: PWM on pin 39 appears to be nonfunctional. We are looking into this issue.
  • VREF is nonfunctional: Due to a routing error, VREF is permanently tied to 3.3V at VAA.

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© Copyright 2010, 2011, LeafLabs, LLC. Last updated on Jan 15, 2014. Created using Sphinx 1.1.3.