Difference between revisions of "User:EnthusiasticGeek/Keyboard Case"
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VBUS VBAT GND</nowiki> | VBUS VBAT GND</nowiki> | ||
The SDA and SCL pins | * The SDA and SCL pins are connected to the PinePhone or PinePhone Pro's I2C bus. This is how the phone and keyboard communincate. | ||
* VBUS connects to the USB +5V line. See [[User:EnthusiasticGeek/Keyboard_Case#Charging Information|Charging Information]] for more information | |||
VBUS connects to the USB +5V line. See [[User:EnthusiasticGeek/Keyboard_Case#Charging Information|Charging Information]] for more information | * The VBAT pin connects to the battery. This powers the keyboard if it is out of power<!--Citation Needed-->. | ||
* INT is a pin that's used for interrupts. In the case of the preinstalled firmware <!--add link to firmware page-->, it is used so the phone can request key presses from the keyboard.<!--Citation Needed--> | |||
<!--I'm pretty sure that INT is just a regular GPIO pin on both the keyboard and PinePhone (Pro), but I'm not sure right now...--> | |||
The VBAT pin connects to the battery. This powers the keyboard if it is out of power<!--Citation Needed-->. | |||
INT is a pin that's used for interrupts. In | |||
<!--I'm pretty sure that INT is just a regular GPIO pin, but I'm not sure right now...--> | |||
=== Charging Information === | === Charging Information === | ||
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The VBUS rail is also accessed through one of the pogo pins on the back of the phone. This is what the keyboard uses to charge the phone. The output of the IP5209 chip<!--explain "the output" better--> is connected to the VBUS rail through this pogo pin, which charges the phone. This makes the keyboard act as a USB charger with only +5V and GND connected, which charges the phone. | The VBUS rail is also accessed through one of the pogo pins on the back of the phone. This is what the keyboard uses to charge the phone. The output of the IP5209 chip<!--explain "the output" better--> is connected to the VBUS rail through this pogo pin, which charges the phone. This makes the keyboard act as a USB charger with only +5V and GND connected, which charges the phone. | ||
==== Problems with Charging Implimentation ==== | |||
The way in which the PinePhone and PinePhone Pro can charge with the keyboard breaks the USB-C spec. If the phone and connected device negotiates that ths phone shall be the sink, or if the connected device does not have any negotiation capabilities but acts as a source, +5V will still be put out by the PinePhone or PinePhone Pro. This means that, for example, a charger plugged into the phone while the keyboard is connected may result in some unintended behaviors.<!--Citation and clarification needed, as well as future links for when people inevitably fry their phones by plugging the charger into the wrong spot ;)--> In the case of the original PinePhone, this is fixable by having the VBUS pin instead connect to the Allwinenr A64's second power input, similar to how it's handled on the [[PineTab]]. However, the RK3399S does not have this feature.<!--Citation needed--> | |||
Revision as of 03:39, 3 January 2022
This Keyboard Case is a case for the PinePhone and PinePhone Pro. As the name implies, it adds a keyboard to the phones. It also has a 6000 mAh battery that essentially tripples the phone's 3000 mAh battery life.
Connectivity
The Keyboard Case has six pins that connect it to the PinePhone or PinePhone Pro.
INT SDA SCL VBUS VBAT GND
- The SDA and SCL pins are connected to the PinePhone or PinePhone Pro's I2C bus. This is how the phone and keyboard communincate.
- VBUS connects to the USB +5V line. See Charging Information for more information
- The VBAT pin connects to the battery. This powers the keyboard if it is out of power.
- INT is a pin that's used for interrupts. In the case of the preinstalled firmware , it is used so the phone can request key presses from the keyboard.
Charging Information
In most schematics, including the PinePhone and PinePhone Pro, the usually +5V coming from the usb connector is named VBUS. This voltage is fed into the System-On-a-Chip in the PinePhone (Allwinner A64) or PinePhone Pro (RK3399S). The SOC then manages this voltage and charges the battery.
The VBUS rail is also accessed through one of the pogo pins on the back of the phone. This is what the keyboard uses to charge the phone. The output of the IP5209 chip is connected to the VBUS rail through this pogo pin, which charges the phone. This makes the keyboard act as a USB charger with only +5V and GND connected, which charges the phone.
Problems with Charging Implimentation
The way in which the PinePhone and PinePhone Pro can charge with the keyboard breaks the USB-C spec. If the phone and connected device negotiates that ths phone shall be the sink, or if the connected device does not have any negotiation capabilities but acts as a source, +5V will still be put out by the PinePhone or PinePhone Pro. This means that, for example, a charger plugged into the phone while the keyboard is connected may result in some unintended behaviors. In the case of the original PinePhone, this is fixable by having the VBUS pin instead connect to the Allwinenr A64's second power input, similar to how it's handled on the PineTab. However, the RK3399S does not have this feature.