Specifications¶
The sections on this page contain information about the Chestnut revision of the Librem 5 phone.
Improvements over Birch¶
Phones in the Chestnut shipment have these improvements over those in the Birch shipment:
The red LED always indicates the charging state, regardless of whether or not the PMIC is powered. (It can illuminate when the phone is “off”.)
Fixed an issue where the TPS65982 was not entering its APP mode when VBUS was presented before the PMIC’s BUCK6 VDD_3V3 rail. This means that rapid charging occurs regardless of whether the TPS65982 is first powered via USB or via the battery – rapid charging always works.
The microSD card is now read-write.
The USB 2.0 D+/D- is now routed directly to the USB-C receptacle so it does not rely on the TPS65982 entering its APP mode to use the data interface. This prevents an extremely unlikely but potential brick situation, which could only really be achieved on a Birch unit if done deliberately.
Improved the WWAN kill switch inrush current such that using a PLS8 M.2 module would not cause the device to reset if you flip the switch off and back on.
Quick Start Guide¶
The version of the Quick Start Guide included with the phone can be downloaded: Librem5-Quick-Start-1.1.0.pdf
Components¶
System on Chip and Peripherals¶
Customer grade i.MX 8M Quad [datasheet] and [reference manual]
Four ARM Cortex-A53 cores.
One Cortex-M4.
Vivante GC7000Lite graphics
1 ⨉ Gigabit Ethernet
32 GB eMMC
3GB RAM
SPI NOR Flash
Real Time Clock (RTC)
Audio¶
Wolfson Media WM8962
Headphones and external microphone via CTIA-configured 3.5mm jack
Loudspeaker
Battery¶
Texas Instruments BQ25895 battery charge controller [datasheet]
Purism branding
Bluetooth, Wi-Fi, WWAN¶
Bluetooth I2S interface
Bluetooth (SDIO)
RedPine WiFi/BT M.2 module on SDIO
Broadmobi BM818-E1 or BM818-A1 WWAN module
Display¶
Mantix MLAF057WE51 MIPI DSI LCD panel: 720x1440 pixels and touch controller
GNSS¶
Teseo-LIV3F multiconstellation GNSS receiver (UART2 interface and antenna)
Hardware Kill Switches¶
Diodes Incorporated Power Switch [datasheet]
WWAN (Modem)
WiFi/Bluetooth
Microphone and Camera
LEDs¶
Used for indicating charging status
Push Buttons¶
Power
Volume up
Volume down
Smart Card¶
Test Points¶
The 15 test points for UART1, UART2, JTAG, and the BOOT_MODE0/1 pins can be found below the WLAN module on the rear of the phone, as shown with the rear cover removed.
See a larger version of this image
The USB test points are located in the recessed area above the battery compartment.
USB¶
Serial Downloader support (loading u-boot via USB)
USB-C port including USB-C role switching
Schematics¶
The following schematics are available:
Librem 5 Chestnut main board:
librem5_chestnut_mainboard_schematic.pdf
Librem 5 Chestnut USB C board:
librem5_chestnut_usb-c_board_schematic.pdf