🧪 extend switchable clock domain (#780)

stnolting · Jan 29, 2024 · 8e52234 · 8e52234
2 parents 1e5811e + 2d469c6
commit 8e52234
Show file tree

Hide file tree

Showing 4 changed files with 9 additions and 7 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -30,6 +30,7 @@ mimpid = 0x01040312 -> Version 01.04.03.12 -> v1.4.3.12
 
 | Date | Version | Comment | Link |
 |:----:|:-------:|:--------|:----:|
+| 29.01.2024 | 1.9.3.9 | :test_tube: extend switchable clock domain (CPU bus switch, i-cache, d-cache) | [#780](https://github.com/stnolting/neorv32/pull/780) |
 | 29.01.2024 | 1.9.3.8 | top entity input ports now have default values `'L'` or `'h'` modeling a pull-down or pull-resistor in case they are not explicitly assigned during instantiation | [#779](https://github.com/stnolting/neorv32/pull/779) |
 | 28.01.2024 | 1.9.3.7 | FIFO module _NULL assertion_ fix | [#778](https://github.com/stnolting/neorv32/pull/778) |
 | 27.01.2024 | 1.9.3.6 | improve CPU's front end (instruction fetch) increasing overall performance | [#777](https://github.com/stnolting/neorv32/pull/777) |

diff --git a/docs/datasheet/soc.adoc b/docs/datasheet/soc.adoc
@@ -311,9 +311,10 @@ before being further processed.
 ==== Clock Gating
 
 The single clock domain of the processor can be split into an always-on clock domain and a switchable clock domain.
-The switchable clock domain is used to clock the CPU core. This domain can be deactivated at runtime to reduce power
-consumption. The always-on clock domain is used to clock all other processor modules like peripherals, memories and IO
-devices. Hence, these modules can continue operation (e.g. a timer keeps running) even if the CPU is shut down.
+The switchable clock domain is used to clock the CPU core, the CPU's bus switch and - if implemented - the caches.
+This domain can be deactivated to reduce power consumption. The always-on clock domain is used to clock all other
+processor modules like peripherals, memories and IO devices. Hence, these modules can continue operation (e.g. a
+timer keeps running) even if the CPU is shut down.
 
 The splitting into two clock domain is enabled by the `CLOCK_GATING_EN` generic (<<_processor_top_entity_generics>>).
 When enabled, a generic clock switching gate is added to decouple the switchable clock from the always-on clock domain

diff --git a/rtl/core/neorv32_package.vhd b/rtl/core/neorv32_package.vhd
@@ -56,7 +56,7 @@ package neorv32_package is
 
   -- Architecture Constants -----------------------------------------------------------------
   -- -------------------------------------------------------------------------------------------
-  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01090308"; -- hardware version
+  constant hw_version_c : std_ulogic_vector(31 downto 0) := x"01090309"; -- hardware version
   constant archid_c     : natural := 19; -- official RISC-V architecture ID
   constant XLEN         : natural := 32; -- native data path width
 

diff --git a/rtl/core/neorv32_top.vhd b/rtl/core/neorv32_top.vhd
@@ -602,7 +602,7 @@ begin
         ICACHE_UC_PBEGIN  => uncached_begin_c(31 downto 28)
       )
       port map (
-        clk_i     => clk_i,
+        clk_i     => clk_cpu,
         rstn_i    => rstn_sys,
         clear_i   => i_fence,
         cpu_req_i => cpu_i_req,
@@ -630,7 +630,7 @@ begin
         DCACHE_UC_PBEGIN  => uncached_begin_c(31 downto 28)
       )
       port map (
-        clk_i     => clk_i,
+        clk_i     => clk_cpu,
         rstn_i    => rstn_sys,
         clear_i   => d_fence,
         cpu_req_i => cpu_d_req,
@@ -655,7 +655,7 @@ begin
       PORT_B_READ_ONLY => true -- i-fetch is read-only
     )
     port map (
-      clk_i   => clk_i,
+      clk_i   => clk_cpu,
       rstn_i  => rstn_sys,
       a_req_i => dcache_req, -- prioritized
       a_rsp_o => dcache_rsp,