Functions
MONITOR_FALLING_EDGES
EDGE DETECTION API

The MONITOR_FALLING_EDGES procedure call monitors a std_logic input signal level for a transition from logic '1' to logic '0'. When a high to low transition is detected, a strobe signal on state_reg_rec(M).rising_edge_reg(N) is asserted to logic '1' value for one clock cycle. The strobe signal occurs 1 clock cycle after the sampled high to low transition of the input signal.

Each resource_index, M, has an array of N falling_edge detect circuits. However, in many use cases, each of individual strobe signal, state_reg_rec(M).falling_edge_reg(N), is not explicitly read.
Instead, the caller of MONITOR_FALLING_EDGES typically specifies a state machine on resource M to transition state after the falling_edge is detected.

There can be multiple falling edge detectors on the same resource domain, thus each individual falling edge detector is identified by a edge_index.

Usage Examples

Todo:
Add Example Usage

Example API Call(s):

MONITOR_FALLING_EDGES(0, input_sig, st_start, next_state_rec, state_reg_rec );

Call Data [ 5 parameters (5 mandatory) ]

Parameters
[in]edge_index[1] index (N) of the array falling_edge_reg vector that is returned by the framework
[in]input_signal[2] signal to be monitored for a low to high transition
[in]transition_state[3] integer state to transition to after a falling edge detection of input_signal
[out]next_state_rec[4]
[in]state_reg_rec[5]

Return Data

Parameters
[in]state_reg_rec(M).falling_edge_reg(N)[1] [std_logic] value returned from framework

Command Reference

Voice and Hotkey Commands:

See also
Monitor Falling Edges Commands

Command Parameter Mapping

Parameters
[in]edge_index[1] "index <integer>"
[in]input_signal[2] "data <std_logic>"
[in]transition_state[3] "go to [state] (<state>|<integer>)"
[out]next_state_rec[4]
[in]state_reg_rec[5]

Command Return Data

Parameters
[in]state_reg_rec(M).falling_edge_reg(N)[1] [std_logic] "falling edge reg <integer>"

Voice/HotKey Command Sequence

MONITOR_FALLING_EDGES( 0, input_signal(1), st_start, next_state_rec, state_reg_rec );

Voice Command HotKey Sequence
"monitor falling edge zero" mf0
"data input signal one" data input_signal(1)
"goto state start" goto st_start

Notes and Warnings

Note
  1. The caller is responsible for indexing falling_edge_reg(N) when the call is made when reading strobes.
  2. When indexing state_reg_rec(M).falling_edge_reg(N), 'M' represents the resource index and 'N' represents the edge_index
  3. A rising_edge detection circuit is utilized when the CONFIGURE_COUNTER call specifies an enable parameter with a boolean expression
See also
MONITOR_RISING_EDGES

Procedures

  MONITOR_FALLING_EDGES(
edge_index: natural
input_signal: std_logic
transition_state: STATE_INTEGER
signal next_state_rec: out NSR
state_reg_rec: in SRR
)
  MONITOR_FALLING_EDGES(
edge_index: natural
input_signal: std_logic
transition_state: STATE_INTEGER
signal next_state_rec: out NSR
state_reg_rec: in SRR
trigger_time: in time
)
  MONITOR_FALLING_EDGES(
edge_index: natural
input_signal: std_logic
transition_state: STATE_INTEGER
signal next_state_rec: out NSR_ARRAY
state_reg_rec: in SRR_ARRAY
)
 overloaded for array interface
  MONITOR_FALLING_EDGES(
edge_index: natural
input_signal: std_logic
transition_state: STATE_INTEGER
signal next_state_rec: out NSR_ARRAY
state_reg_rec: in SRR_ARRAY
trigger_time: in time
)