updated README.md
diff --git a/README.md b/README.md
index d2efa54..3978e22 100644
--- a/README.md
+++ b/README.md
@@ -1,10 +1,40 @@
-# Caravel User Project
+# GF180 PWM/Wishbone core #
[](https://opensource.org/licenses/Apache-2.0) [](https://github.com/efabless/caravel_project_example/actions/workflows/user_project_ci.yml) [](https://github.com/efabless/caravel_project_example/actions/workflows/caravel_build.yml)
-| :exclamation: Important Note |
-|-----------------------------------------|
+A basic pulse with modulation core with 8 PWMs controled by a wishbone bus slave interface. The PWMs are 8-bit programmable
+with full range of duty cycle control. All PWMS run synchronized to a single counter.
-## Please fill in your project documentation in this README.md file
+## Detailed documentation ##
-Refer to [README](docs/source/index.rst) for this sample project documentation.
+A simple pulse width modulator connected to a wishbone
+bus. Given an input clock signal, it is capable of dividing
+the signal by 2^n where 0 <= n < 24. This allows a 100MHz core
+fequency to be stepped down to just under 6 Hz if need be. The
+frequency of each PWM is individually controlled by the
+*Divider* registers which store the value n\_i for PWM i. The
+ *Threshold* register sets the duty cycle for each PWM such
+ that its value v\_i has duty cycle (256-v\_i)/256 and valid
+ v\_i values are 0 < v\_i <= 255. Note that v\_i=0 turns off
+ PWM i.
+
+### Wishbone base address: 0xFEED0000 ###
+
+### Registers: ###
+* 0000 Threshold 0
+* 0001 Threshold 1
+* 0002 Threshold 2
+* 0003 Threshold 3
+* 0004 Threshold 4
+* 0005 Threshold 5
+* 0006 Threshold 6
+* 0007 Threshold 7
+* 0008 Divider 0
+* 0009 Divider 1
+* 000a Divider 2
+* 000b Divider 3
+* 000c Divider 4
+* 000d Divider 5
+* 000e Divider 6
+* 000f Divider 7
+
