cardem: ensure VCC_PHONE is floating

this change is mainly relevant for the SIMtrace board, but also
affects the others.
First we ensure VCC_PHONE is not forwarded to VCC_SIM because the
card could affect the signal (card could draw too much current or
feed back current in).
next we disable VCC_SIM. the card slot does not need to be
powered, and the FPF2019 leaks current back to VCC_PHONE, even
with forwarding disabled (the reverse current protection only
kicks in when VCC_PHONE is briefly shorted to ground, but still
leaks 0.6V).
enable the ADC channels normally used to measure VCC, even if
not used. the dedicated ADC pins leak current when left
unconfigured. enabling them puts them in high impedance.

Change-Id: If1487c1c191838aaa08b654e49cd31c7180ffc19
This commit is contained in:
Kévin Redon
2019-07-18 18:50:51 +02:00
parent 76c2eebae2
commit 90abc09cf3
2 changed files with 17 additions and 1 deletions

View File

@@ -105,6 +105,14 @@
/* ISO7816-communication related pins */
#define PINS_ISO7816 PIN_SIM_IO, PIN_SIM_CLK, PIN_ISO7816_RSTMC // SIM_PWEN_PIN, PIN_SIM_IO2, PIN_SIM_CLK2
/** card emulation configuration */
/* Disable power converter 4.5-6V to 3.3V (active high) */
#define PIN_SIM_PWEN_CARDEMU {SIM_PWEN, PIOA, ID_PIOA, PIO_OUTPUT_0, PIO_DEFAULT}
/* Disable power switch to forward VCC_PHONE to VCC_SIM (active high) */
#define PIN_VCC_FWD_CARDEMU {VCC_FWD, PIOA, ID_PIOA, PIO_OUTPUT_0, PIO_DEFAULT}
/* Disable power to SIM */
#define PINS_PWR_CARDEMU PIN_SIM_PWEN_CARDEMU, PIN_VCC_FWD_CARDEMU
/** External SPI flash interface **/
/* SPI MISO pin definition */
#define PIN_SPI_MISO {PIO_PA12A_MISO, PIOA, PIOA, PIO_PERIPH_A, PIO_PULLUP}