better names and sectioning

1 files changed, 9 insertions, 10 deletions

diff --git a/microwire.lua b/microwire.lua
index cc98a68..d6c1ff4 100644
--- a/microwire.lua
+++ b/microwire.lua
@@ -1,28 +1,27 @@
 -- functions to write registers over microwire interface
--- it resembles SPI but need exrta pin which sends Load Enable (LE) pulse
--- otherwise SPI sequence is sent into 24 bit FIFO buffer 
+-- it resembles SPI but need extra pin which sends Load Enable (LE) pulse
+-- otherwise SPI sequence is sent into 24 bit FIFO latch register on chip
 
 -- Pins assignment
 -- SPI Id selects which pins are used for CLK, MOSI, MISO, CS
-spiID = 1; -- ID=1 --> HSPI in nodemcu language
-databits=24; -- LMX2487 loads 24 bits sequence per write into a register
--- default SPI clock is 80 MHz
-fSPI = 80000000
+microwire_spiID = 1; -- ID=1 --> HSPI in nodemcu language
+microwire_databits=24; -- LMX2487 loads 24 bits sequence per write into a register
 -- lmx2487 can handle up to 20 MHz speed (50 nS per clock) but optocoupler is good for 240kHz
 -- so let's aim for 100 kHz
-maxMicrowireInterfaceSpeed = 100000; -- in Hz
-clock_divider = math.floor(fSPI/maxMicrowireInterfaceSpeed)
+microwire_interface_speed = 100000; -- in Hz
 
 -- we will use SPI ChipSelect pin for LoadEnable pin
 microwire_LE_pin = 8; -- microwire Load Enable pin. 8 --> GPIO15
 
 function microwire_setup_interface ()
+	local fSPI = 80000000; -- default SPI clock is 80 MHz
+	local clock_divider = math.floor(fSPI/microwire_interface_speed)
 	-- now microwire <--> SPI setup
 	-- microwire is SPI with CPOL=0 and CPHA=0 i.e. SPI mode 0 = 00 = CPOL.CPHA
 	-- see https://en.wikipedia.org/wiki/Serial_Peripheral_Interface#Mode_numbers
 	-- see https://www.totalphase.com/support/articles/200348506-Using-the-Aardvark-adapter-with-a-Microwire-device
 	-- we are setting SPI Id = 1, since Id = 0 used for communication with memory
-	spi.setup(spiID, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, databits, clock_divider)
+	spi.setup(microwire_spiID, spi.MASTER, spi.CPOL_LOW, spi.CPHA_LOW, microwire_databits, clock_divider)
 	-- SPI Id=1 uses following pins https://nodemcu.readthedocs.io/en/master/modules/spi
 	-- Signal    | IO index | ESP8266 pin
 	-- HSPI CLK  | 5        | GPIO14
@@ -45,7 +44,7 @@ function microwire_send_data( data )
 	gpio.write(microwire_LE_pin, gpio.LOW)
 
 	-- second send the data
-	local nBytes = spi.send(spiID, data)
+	local nBytes = spi.send(microwire_spiID, data)
 
 	
 	-- finally raise LE pin for at least 25 ns,