NXP Semiconductors UM11579, Руководство пользователя

Страница: 8 / 41

NXP Semiconductors
UM11579
PCA9957HN-ARD evaluation board
because the control input is pulled up (high state) through R89. When a secondary
board is inserted into the Fuji output connector, the U5 control input located on the first
board is pulled down to ground through pin 3 of J46 and J47 of the next board. When
the switch U5 (first board) is open, the signal path of the SPI is: MOSI (Arduino port)
– SDI input (U2, first board) – SDO output (U2, first board) – pin 6 (J46 first board) –
pin 6 (J47 second board) – SDI (U2, second board) – SDO (U2, second board) – U5
(second board which is closed) – pin 8 (J47, second board – pin 8 (J46, first board) –
MISO (Arduino port). The daisy chain loop is then closed through both DUT's on the two
inter-connected daughter boards. The SPI clock and chip select lines are sent directly to
the DUT (U2) on the first card, and through the Fuji connectors to the secondary card.
For SPI characteristics and data format, see the PCA9957 datasheet Table 1 and Table
2, which details the pin map of the Arduino port and the Fuji connectors.
Note 2: For IMXRT1050 EVK, the SPI lines on the EVK board are not linked to the
Arduino connector. Before using the EVK, the user must populate the DNP zero-ohm
resistors R278 to R281 (see the EVK schematic diagram file SPF-30168_A1.pdf,
available at
www.nxp.com .
5.7 Arduino port
The connectors J5, J6, J35, and J36 are the mated pin headers of Arduino Uno R3
connectors, having the same electrical function and being placed on the board so that the
daughter board can be directly inserted in the Arduino port. The daughter board circuit
uses only seven signal lines. Table 2 shows the Arduino connector pins and how they are
used in the circuit (see also the SPF-46841.pdf schematic file).
Note 3: A4 / SDA common line for J2 – 5 and J4 – 9. A5 / SCL common line for J2 – 6 and J4 – 10.
Ref Des # Arduino label PCA9957HN-ARD function
1 NC Not used
2 IOREF Not used
3 RESET Not used
4 3.3V Power supply
5 5V Not used
6 GND Power supply return
7 GND Power supply return
J6 (Power)
8 Vin Not used
1 A0 Not used
2 A1 Not used
3 A2 Not used
4 A3 Not used
5 A4 / SDA
(Note 2)
Not used
J35 (analog, digital, I
2
C)
6 A5 / SCL
(Note 2)
Not used
1 D0 / RX Not used
2 D1 / TX Not used J5 (digital, UART, PWM)
3 D2 REXT SELECT (SW_EN)
Table 2. The pin chart of Arduino connectors and their usage
UM11579 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2021. All rights reserved.
User manual Rev. 1 — 25 February 2021
8 / 41