UART » History » Revision 55
Revision 54 (Denis 'GNUtoo' Carikli, 03/08/2020 01:58 AM) → Revision 55/93 (Denis 'GNUtoo' Carikli, 03/08/2020 01:59 AM)
h1. UART
There is an in-depth article covering several Samsung devices in the [[SamsungSerial]] page
h2. Settings
|_. Device and documentation |_. I/O voltage |_. ID<->GND |_. SOC TX |_. SOC RX |_. switch |_. stock bootloader settings |_. Comments |
| GT-I9100 | | 510k | | | "MAX8997":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/arch/arm/configs/lineageos_i9100_defconfig#n1294 | 115200 8N1 | * You need to press the volume-down button during boot to see the logs
* At some point the boot procedure switches to the modem UART, it's probably some linux driver doing that |
| GT-I9100G_CHN_CHN | 1.8V[8] ? | 619k[9] | D- | D+ | ? | 115200 8N1 | Very few prints from Xloader, the next bootloader used by Android 2.6.3 doesn't seem to print much |
| GT-I9300 |/2. 1.8V[1] |/4. 619 kOhms[3] |/4. D- |/4. D+ |/4. MAX77693[5] |/4. * speed: 115200
* pressing the volume-down button during boot increase verbosity |/2. It gives a shell once Replicant 6 has booted |
| GT-I9305 |
| GT-N7100 | ? | |
| GT-N7105 | ? | |
| [[GalaxyNexusI9250SerialConsole|Galaxy Nexus (GT-I9250)]] | | 619 kOhms[4] | D+ | D- | FSA9480[7] | * By default: ttyFIQ0, 115200 8N1
* With patching: ttyO2, 115200 8N1
See [[GalaxyNexusI9250SerialConsole]] for more details. | |
| [[NexusSI902xSerial|Nexus S]] | | 150 kOhm | | | FSA9480 | | |
| [[OptimusBlackSerial|Optimus Black (P970)]] | 1.8V[6] | N/A[2] | | | DP3T | | |
| ODROID-U3, console UART | 1.8V |\4. "connector":https://wiki.odroid.com/accessory/development/usb_uart_kit#odroid_port_description_of_uart_connector | ttySAC1, 115200 8N1 | |
| ODROID-U3, IO pins UART | 1.8V |\4. "connector":https://wiki.odroid.com/old_product/odroid-x_u_q/odroid_u3/u3_ioport_uart | ttySAC0, 115200 8N1 | |
fn1. Measured between USB GND and USB VCC
fn2. Code is required to use the switch as you need to configure both the MUIC and DP3T switch
fn3. See "The related driver source code":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/max77693-muic.c#n102
fn4. See the "postmarketOS wiki page on Serial debugging":https://wiki.postmarketos.org/wiki/Serial_debugging
fn5. See the "driver":https://git.replicant.us/replicant/kernel_samsung_smdk4412/tree/drivers/misc/max77693-muic.c and the "ifixit teardown":https://www.ifixit.com/Teardown/Samsung+Galaxy+S+III+Teardown/9391
fn6. Reference: [[OptimusBlackSerial]]
fn7. See "board-tuna-connector.c":https://git.replicant.us/replicant/kernel_samsung_tuna/tree/arch/arm/mach-omap2/board-tuna-connector.c "fsa9480.c":https://git.replicant.us/replicant/kernel_samsung_tuna/tree/drivers/misc/fsa9480.c in "kernel_samsung_tuna":https://git.replicant.us/replicant/kernel_samsung_tuna
fn8. Works, as it was tested on the device. TODO: measure the voltage, as lower UART voltages often works with higher voltage levels.
fn9. Works, as it was tested on the device. TODO: look the official reference in the driver for it.
h2. Datasheets
* "FSA9480.pdf":https://media.digikey.com/pdf/Data%20Sheets/Fairchild%20PDFs/FSA9480.pdf
h2. Interesting links
* There is a "page on Serial debugging":https://wiki.postmarketos.org/wiki/Serial_debugging on the postmarketOS wiki that contains information for using the serial port for many smartphones models.
* "mv-uart":https://osmocom.org/projects/mv-uart/wiki A serial port adapter with configurable voltages (and GPIOs)
* "DHylands_SGS2_SerialAdapter":https://wiki.mozilla.org/DHylands_SGS2_SerialAdapter : A very compact setup but with fixed resistor value.