From fec6ee365cac76f3dbb9e81bd544eefe8f6dbc76 Mon Sep 17 00:00:00 2001
From: Joel Challis <git@zvecr.com>
Date: Thu, 2 Apr 2020 22:23:57 +0100
Subject: Initial support for ATtiny85 (#8632)

* Initial support for ATtiny85

* Update mcu selection
---
 quantum/config_common.h          |  3 +++
 quantum/mcu_selection.mk         | 15 +++++++++++++++
 tmk_core/common/avr/bootloader.c | 10 +++++-----
 tmk_core/common/avr/timer.c      | 19 +++++++++++++------
 4 files changed, 36 insertions(+), 11 deletions(-)

diff --git a/quantum/config_common.h b/quantum/config_common.h
index b3abdee774..1ad9bfe0da 100644
--- a/quantum/config_common.h
+++ b/quantum/config_common.h
@@ -64,6 +64,9 @@
 #        define PINB_ADDRESS 0x3
 #        define PINC_ADDRESS 0x6
 #        define PIND_ADDRESS 0x9
+#    elif defined(__AVR_ATtiny85__)
+#        define ADDRESS_BASE 0x10
+#        define PINB_ADDRESS 0x6
 #    else
 #        error "Pins are not defined"
 #    endif
diff --git a/quantum/mcu_selection.mk b/quantum/mcu_selection.mk
index e3b4c3f7e3..2fc3a8f4c0 100644
--- a/quantum/mcu_selection.mk
+++ b/quantum/mcu_selection.mk
@@ -290,3 +290,18 @@ ifneq (,$(filter $(MCU),atmega328p))
   NO_UART ?= yes
   NO_SUSPEND_POWER_DOWN ?= yes
 endif
+
+ifneq (,$(filter $(MCU),attiny85))
+  PROTOCOL = VUSB
+
+  # Processor frequency.
+  #     This will define a symbol, F_CPU, in all source code files equal to the
+  #     processor frequency in Hz. You can then use this symbol in your source code to
+  #     calculate timings. Do NOT tack on a 'UL' at the end, this will be done
+  #     automatically to create a 32-bit value in your source code.
+  F_CPU ?= 16500000
+
+  # unsupported features for now
+  NO_UART ?= yes
+  NO_SUSPEND_POWER_DOWN ?= yes
+endif
diff --git a/tmk_core/common/avr/bootloader.c b/tmk_core/common/avr/bootloader.c
index ca9746f327..7e5d2b0579 100644
--- a/tmk_core/common/avr/bootloader.c
+++ b/tmk_core/common/avr/bootloader.c
@@ -237,17 +237,17 @@ void bootloader_jump(void) {
                  "bootloader_startup_loop%=:         \n\t"
                  "rjmp bootloader_startup_loop%=     \n\t"
                  :
-                 : [ mcucsrio ] "I"(_SFR_IO_ADDR(MCUCSR)),
+                 : [mcucsrio] "I"(_SFR_IO_ADDR(MCUCSR)),
 #    if (FLASHEND > 131071)
-                   [ ramendhi ] "M"(((RAMEND - 2) >> 8) & 0xff), [ ramendlo ] "M"(((RAMEND - 2) >> 0) & 0xff), [ bootaddrhi ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
+                   [ramendhi] "M"(((RAMEND - 2) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 2) >> 0) & 0xff), [bootaddrhi] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 16) & 0xff),
 #    else
-                   [ ramendhi ] "M"(((RAMEND - 1) >> 8) & 0xff), [ ramendlo ] "M"(((RAMEND - 1) >> 0) & 0xff),
+                   [ramendhi] "M"(((RAMEND - 1) >> 8) & 0xff), [ramendlo] "M"(((RAMEND - 1) >> 0) & 0xff),
 #    endif
-                   [ bootaddrme ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [ bootaddrlo ] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
+                   [bootaddrme] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 8) & 0xff), [bootaddrlo] "M"((((FLASH_SIZE - BOOTLOADER_SIZE) >> 1) >> 0) & 0xff));
 
 #else  // Assume remaining boards are DFU, even if the flag isn't set
 
-#    if !(defined(__AVR_ATmega32A__) || defined(__AVR_ATmega328P__))  // no USB - maybe BOOTLOADER_BOOTLOADHID instead though?
+#    if !(defined(__AVR_ATmega32A__) || defined(__AVR_ATmega328P__) || defined(__AVR_ATtiny85__))  // no USB - maybe BOOTLOADER_BOOTLOADHID instead though?
     UDCON  = 1;
     USBCON = (1 << FRZCLK);  // disable USB
     UCSR1B = 0;
diff --git a/tmk_core/common/avr/timer.c b/tmk_core/common/avr/timer.c
index 88fa1dfa65..c2e6c6e081 100644
--- a/tmk_core/common/avr/timer.c
+++ b/tmk_core/common/avr/timer.c
@@ -45,19 +45,26 @@ void timer_init(void) {
 #    error "Timer prescaler value is not valid"
 #endif
 
-#ifndef __AVR_ATmega32A__
+#if defined(__AVR_ATmega32A__)
+    // Timer0 CTC mode
+    TCCR0 = _BV(WGM01) | prescaler;
+
+    OCR0  = TIMER_RAW_TOP;
+    TIMSK = _BV(OCIE0);
+#elif defined(__AVR_ATtiny85__)
     // Timer0 CTC mode
     TCCR0A = _BV(WGM01);
     TCCR0B = prescaler;
 
-    OCR0A  = TIMER_RAW_TOP;
-    TIMSK0 = _BV(OCIE0A);
+    OCR0A = TIMER_RAW_TOP;
+    TIMSK = _BV(OCIE0A);
 #else
     // Timer0 CTC mode
-    TCCR0 = _BV(WGM01) | prescaler;
+    TCCR0A = _BV(WGM01);
+    TCCR0B = prescaler;
 
-    OCR0  = TIMER_RAW_TOP;
-    TIMSK = _BV(OCIE0);
+    OCR0A  = TIMER_RAW_TOP;
+    TIMSK0 = _BV(OCIE0A);
 #endif
 }
 
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