From 2e1cc913f6e1964b5b422c6750b8310da7ff2512 Mon Sep 17 00:00:00 2001
From: Nathaniel Wesley Filardo <nwfilardo@gmail.com>
Date: Sat, 10 Oct 2020 14:07:48 +0100
Subject: [PATCH] An initial version of a minimal ht16k33 driver

---
 ht16k33/ht16k33.lua | 92 +++++++++++++++++++++++++++++++++++++++++++++
 ht16k33/pinouts.txt | 32 ++++++++++++++++
 2 files changed, 124 insertions(+)
 create mode 100644 ht16k33/ht16k33.lua
 create mode 100644 ht16k33/pinouts.txt

diff --git a/ht16k33/ht16k33.lua b/ht16k33/ht16k33.lua
new file mode 100644
index 0000000..3f5239f
--- /dev/null
+++ b/ht16k33/ht16k33.lua
@@ -0,0 +1,92 @@
+-- A very minimal HT16K33 driver, fitting for such a minimal chip!
+
+local M = {}
+
+local function tx(self, ...)
+  local i2c, bus, addr = i2c, self.bus, self.addr
+  i2c.start(bus)
+  i2c.address(bus, addr, i2c.TRANSMITTER) 
+  i2c.write(bus, ...)
+  i2c.stop(bus)
+end
+
+local function txrx(self, w, rn)
+  local i2c, bus, addr = i2c, self.bus, self.addr
+  i2c.start(bus)
+  i2c.address(bus, addr, i2c.TRANSMITTER) 
+  i2c.write(bus, w)
+  i2c.start(bus)
+  i2c.address(bus, addr, i2c.TRANSMITTER) 
+  local ret = i2c.read(rn)
+  i2c.stop(bus)
+  return ret
+end
+
+-- control the primary oscillator
+local function osc(self,on)
+  return tx(self, on and 0x21 or 0x20)
+end
+M.osc = osc
+
+M.BLINK_NONE = 0
+M.BLINK_2HZ  = 1
+M.BLINK_1HZ  = 2
+M.BLINK_05HZ = 3
+local function conf(self, blink, on)
+  return tx(self, 0x80 + (blink*2) + (on and 1 or 0))
+end
+M.conf = conf
+
+M.KEYROW_ROW = 0
+M.KEYROW_INT_LO = 1
+M.KEYROW_INT_HI = 3
+function M:rowint(how) -- configure last row as row or interrupt
+  return tx(self, 0xA0 + how)
+end
+
+-- Set brightness between 0 (which is not off, just dim) and 15
+function M:dim(bright)
+  return tx(self, 0xE0 + bright)
+end
+
+-- write what (str int or string with #str <= 16) where (default to 0, 0 to 15)
+--
+-- Recall that device display memory is organized by COM then ROW: the first
+-- byte here is COM0 ROW0 (LSB) through COM0 ROW7 (MSB), then COM0 ROW8 (LSB)
+-- through COM0 ROW15 (MSB), then COM1 ROW0 (LSB) through COM1 ROW7 (MSB), etc.
+function M:write(what, where)
+  where = where or 0x00
+  if type(what) == "table"
+   then return tx(self, where, table.unpack(what))
+   else return tx(self, where, what)
+  end
+end
+
+function M:readint()
+  return txrx(self, "\096", 1)
+end
+
+function M:readkey()
+  return txrx(self, "\064", 5)
+end
+
+local function blank(self)
+  self:write("\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0")
+end
+M.blank = blank
+
+-- a convenience method for default initialization
+function M:init()
+  osc(self, true)
+  blank(self)
+  conf(self, 0, true)
+end
+
+M.__index = M
+
+return function(bus, addr)
+  local self = setmetatable({}, M)
+  self.bus, self.addr = bus, addr
+
+  return self
+end
diff --git a/ht16k33/pinouts.txt b/ht16k33/pinouts.txt
new file mode 100644
index 0000000..5c9cdb5
--- /dev/null
+++ b/ht16k33/pinouts.txt
@@ -0,0 +1,32 @@
+Adafruit 8x16 Feather
+=====================
+
+::
+
+               [          12 pin header            ]
+          ROW0 ROW2 ... ROW14 || ROW1 ROW3 ... ROW15
+    COM7
+    ...
+    COM0
+          [             16 pin header              ]
+
+SparkFun Qwiic Alphanumeric
+===========================
+
+The COLON is at ROW8 COM0 and the DOT is at ROW8 COM1.  There is nothing else
+on ROW8.
+
+Each individual digit, rendered in ASCII ART and with letters stolen from the
+manufacturer's datasheet, looks like this::
+
+                    * Digits each occupy two ROWs, always 4 apart.
+      AAAAAAA   
+    FH   J   KB     * Digits left to right are on ROW0(4) through ROW3(7).
+    F H  J  K B 
+    F  H J K  B     * Within each digit, segments are assigned to their COMs
+      G1   G2         as follows:
+    E  N M L  C 
+    E N  M  L C           A  B  C  D  E  F  G1 G2 H  J  K  L  M  N
+    EN   M   LC       COM 0  1  2  3  4  5  6  0  1  2  3  4  5  6
+      DDDDDDD         ROW 0  0  0  0  0  0  0  4  4  4  4  4  4  4
+
-- 
2.50.1