diff --git a/doc/system_description/software.md b/doc/system_description/software.md
index 59df06f..5e5ef94 100644
--- a/doc/system_description/software.md
+++ b/doc/system_description/software.md
@@ -327,13 +327,13 @@ Assigned core prefixes:
 
 | *name*            | *fw*  | *app       | *size* | *type*   | *content* | *description*                                                         |
 |-------------------|-------|------------|--------|----------|-----------|-----------------------------------------------------------------------|
-| `TRNG_STATUS`     | r     | r          |        |          |           | STATUS_READY_BIT is set when an entropy word is available.            |
+| `TRNG_STATUS`     | r     | r          |        |          |           | TRNG_STATUS_READY_BIT is 1 when an entropy word is available.         |
 | `TRNG_ENTROPY`    | r     | r          | 4B     | u32      |           | Entropy word. Reading a word will clear status.                       |
-| `TIMER_CTRL`      | r/w   | r/w        |        |          |           | If bit 0 in TIMER_STATUS is set then writing here starts the timer.   |
-|                   |       |            |        |          |           | If bit 0 in TIMER_STATUS is unset then writing here stops the timer.  |
-| `TIMER_STATUS`    | r     | r          |        |          |           | If bit 0 is set, the timer is ready to start running.                 |
+| `TIMER_CTRL`      | r/w   | r/w        |        |          |           | If TIMER_STATUS_READY_BIT in TIMER_STATUS is 1 then writing here      |
+|                   |       |            |        |          |           | starts the timer. If the same bit is 0 then writing stops the timer.  |
+| `TIMER_STATUS`    | r     | r          |        |          |           | TIMER_STATUS_READY_BIT is 1 when timer is ready to start running.     |
 | `TIMER_PRESCALER` | r/w   | r/w        | 4B     |          |           | Prescaler init value. Write blocked when running.                     |
-| `TIMER_TIMER`     | r/w   | r/w        | 4B     |          |           | Timer init or current value when running. Write blocked when running. |
+| `TIMER_TIMER`     | r/w   | r/w        | 4B     |          |           | Timer init or current value while running. Write blocked when running.|
 | `UDS_FIRST`       | r[^3] | invisible  | 4B     | u8[32]   |           | First word of Unique Device Secret key.                               |
 | `UDS_LAST`        |       | invisible  |        |          |           | The last word of the UDS                                              |
 | `UART_BITRATE`    | r/w   |            |        |          |           | TBD                                                                   |
@@ -343,7 +343,8 @@ Assigned core prefixes:
 | `UART_RX_DATA`    | r     | r          | 1B     | u8       |           | Data to read. Only LSB contains data                                  |
 | `UART_TX_STATUS`  | r     | r          | 1B     | u8       |           | Non-zero when it's OK to write data                                   |
 | `UART_TX_DATA`    | w     | w          | 1B     | u8       |           | Data to send. Only LSB contains data                                  |
-| `TOUCH_STATUS`    | r/w   | r/w        |        |          |           | STATUS_EVENT_BIT is set when touched; write to it after               |
+| `TOUCH_STATUS`    | r/w   | r/w        |        |          |           | TOUCH_STATUS_EVENT_BIT is 1 when touched. After detecting a touch     |
+|                   |       |            |        |          |           | event (reading a 1), write anything here to acknowledge it.           |
 | `FW_RAM`          | r/w   | invisible  | 1 kiB  | u8[1024] |           | Firmware-only RAM.                                                    |
 | `UDA`             | r     | invisible  | 16B    | u8[16]   |           | Unique Device Authentication key.                                     |
 | `UDI`             | r     | r          | 8B     | u64      |           | Unique Device ID (UDI).                                               |