feat: Add short documentation

README.adoc

-
-# PSCGEN: Signal generator for Power Supplies Controller
+include::doc/main.adoc[]

doc/main.adoc

+= Power Supply Controller Generator
+
+// ================================================================================
+== Description
+This module can generate sine waveform for multiple power supplies.
+It is built to work in association with ComCorr IP.
+
+The module outputs waveform as signed values on its TDATA output.
+The TUSER output carries the Identifier of the waveform.
+
+It is possible to generate up to `2**C_W_TIDX` (default 255) Identifiers.
+Each waveform has independents parameters:
+* Phase increment
+* Phase offset
+* Scaling value
+* Offset value
+* Reset phase
+
+The module generate data values every `TICKER_RATE` clock period.
+At each of this tick, the phase of all waveform is incremented and a new wave value is computed for each waveform.
+The values are output via the AXI-Stream Output, one value transaction by transfer.
+
+// ================================================================================
+== Runtime configuration
+The generator will compute and ouput values for Identifier from `TABLE_DEPTH` downto 0.
+Entries in the `TABLE_PHASE` and `TABLE_SCALE` for these Identifier shall be configured by the user.
+These two tables are addressed by the Identifier number.
+Data values pack configuration, as descrived below.
+
+.TABLE_PHASE data pack.
+|===
+| `31-2*C_W_PHASE` bits |1 bit | `C_W_PHASE` bits  | `C_W_PHASE` bits  |
+| unused |Reset accumulator | Phase offset | Phase increment |
+|===
+
+.TABLE_SCALE data pack.
+|===
+| `32-C_W_OFFSET-C_W_SCALE` bits | `C_W_OFFSET` bits  | `C_W_SCALE` bits  |
+| unused | Signal Offset | Signal Scale Factor |
+|===
+
+The DDS contained in the module receive the phase value, computed from the sum of the accumulator and the *Phase Offset* configuration.
+The accumulator is incremented by the *Phase Increment* at each tick.
+The result roll over the max value.
+
+The output of the DDS is multiplied by the *Signal Scale Factor*, which is considered as a fixed point value, containing only decimals.
+(The DDS is configured to genrate full scale sine values).
+The *Signal Offset* is then applied, aligned on the fixed point (no decimals).
+The final result is scrapped of decimals values.
+
+
+// ================================================================================
+== Registers map
+include::registers.adoc[]

doc/registers.adoc

+.Register
+[.tab-addr-reg,cols="5,1,1,2,1,9"]
+|===
+|Name | N | bits | type | RW | Description
+
+| ID                                       |    1 |   32 | uint |   RO | +++Module Identification Number+++  
+| VERSION                                  |    1 |   32 | uint |   RO | +++Module Version Number+++  
+| CONTROL                                  |    1 |    1 | uint |   RW | +++Control register+++  
+| TICKER_RATE                              |    1 |   32 | uint |   RW | +++Ticker rate register+++  
+| TABLE_DEPTH                              |    1 |    8 | uint |   RW | +++Table scan depth register+++  
+|===
+
+.Memories
+[.tab-addr-mem,cols="5,2,1,2,1,8"]
+|===
+|Name | N | bits | type | RW | Description
+
+| TABLE_PHASE                                  |  256      |   31 | uint |   RW | +++Phase increment and offset table+++ 
+| TABLE_SCALE                                  |  256      |   32 | uint |   RW | +++Signal scale and offset table+++ 
+|===
+