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-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

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)