added aknowledge pulse to ihu-ttx communication

git-svn-id: https://svn.spreadspace.org/mur.sat@239 7de4ea59-55d0-425e-a1af-a3118ea81d4c

4 files changed, 109 insertions, 8 deletions

diff --git a/doc/protocols/ihu-ttx.txt b/doc/protocols/ihu-ttx.txt
index d4fdcec..c91c479 100644
--- a/doc/protocols/ihu-ttx.txt
+++ b/doc/protocols/ihu-ttx.txt
@@ -14,6 +14,10 @@ The data is transferred MSB first in groups of 8bits (1 Octet). SDA must be
 stable before the clock goes high. A Clock pulse must be at least 4µs long and 
 the data has to stay valid for at least 17µs. After each octet there must be a 
 break of 50µs.
+After the last octet, which will be a checksum generated by the slave, the master 
+has to generate a single bit aknowledge. A logic low on SDA during a SCL pulse
+instructs the slave to process the received frame whereas a logic high tells the 
+slave to discard all data and proceed with normal operation.
 
 
      | wake up |               1st octet                        | break  |  2nd octet
@@ -33,13 +37,16 @@ Frames
 Every frame starts with 4 bit command code and a 4 bit length field. After this follow
 LEN octets of data. When all the data has been transferred the master (IHU) switches
 SDA to input and clocks in on byte as acknowledge. The aknowledge is a one byte XOR
-checksum over all octets (including the CMD/LEN octet).
+checksum over all octets (including the CMD/LEN octet). 
 
 Field-length:    1           LEN           1
             +---------+----------------+--------+
 Name        | CMD/LEN |      DATA      |   CS   |
             +---------+----------------+--------+
 
+As stated earlier a frame has only to be processed when a positive aknowledge has been
+sent by the master.
+
 Commands
 --------
 
@@ -97,3 +104,4 @@ Commands
  This transmits a new format string for the standard beacon. The data is a variable
  length string containing ASCII characters each standing for a beacon element to send
  out.
+ 
diff --git a/software/ihu/ihu.asm b/software/ihu/ihu.asm
index cec3e51..c213698 100644
--- a/software/ihu/ihu.asm
+++ b/software/ihu/ihu.asm
@@ -369,6 +369,78 @@ uart_rx_fe
 main
 ;  sleep
 ;  nop
+  ;; --------------------
+  ;; TTX Test
+  movf      TMP,w
+  btfsc     STATUS,Z
+  goto      main
+
+  movwf     BUF
+  clrf      TMP
+  movlw     BUF+1
+  movwf     FSR
+  
+  movlw     .1
+  movwf     TTX_BYTE_CNT
+main_read_bytes
+  movf      TMP,w
+  btfsc     STATUS,Z
+  goto      main_read_bytes
+  movwf     INDF
+  incf      FSR,f
+  clrf      TMP
+  decfsz    TTX_BYTE_CNT,f
+  goto      main_read_bytes
+
+  movlw     BUF
+  movwf     FSR
+  movlw     0xA2
+  call      ttx_send
+
+  xorlw     .0
+  btfss     STATUS,Z
+  goto      main_error
+  
+  movlw     'O'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     'K'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     '\r'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     '\n'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  goto      main
+  
+main_error
+  movlw     'E'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     'R'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     'R'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     '\r'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms
+  movlw     '\n'
+  movwf     TXREG
+  movlw     .1
+  call      wait_ms  
+  goto      main
 
   ;; --------------------
   ;; ADC Test
diff --git a/software/ihu/ttx.inc b/software/ihu/ttx.inc
index b9f45e7..2098340 100644
--- a/software/ihu/ttx.inc
+++ b/software/ihu/ttx.inc
@@ -108,7 +108,7 @@ ttx_send_frame
 
   movf      TTX_BYTE_CNT,f
   btfsc     STATUS,Z
-  return
+  goto      ttx_get_csum
 
 ttx_next_byte
   call      ttx_break
@@ -119,16 +119,31 @@ ttx_next_byte
   decfsz    TTX_BYTE_CNT,f
   goto      ttx_next_byte
 
+ttx_get_csum
   call      ttx_break
   call      ttx_recv_byte
   movf      TTX_BYTE,w
   xorwf     TTX_CSUM,w  
   btfss     STATUS,Z
   goto      ttx_csum_error
-  return    
+  retlw     .0
 
 ttx_csum_error
-  ;; TODO: react to comm error
-  return
+  retlw     .1
 
   ;; -------------------------------------
+ttx_send
+  call      ttx_send_frame
+  movwf     TTX_BYTE
+  call      ttx_break
+  btfsc     TTX_BYTE,0
+  bcf       PORTD,TTX_SDA
+  btfss     TTX_BYTE,0
+  bsf       PORTD,TTX_SDA
+  bsf       PORTD,TTX_SCL
+  nop
+  nop
+  nop
+  bcf       PORTD,TTX_SCL
+  return
+  ;; -------------------------------------
diff --git a/software/ttx/ttx.asm b/software/ttx/ttx.asm
index 6e974c9..0f75420 100644
--- a/software/ttx/ttx.asm
+++ b/software/ttx/ttx.asm
@@ -76,7 +76,7 @@ RX_BIT_CNT  EQU H'004E'
 RX_BYTE_CNT EQU H'004F'
 RX_CMD      EQU H'0050'
 RX_D_START  EQU H'0051'
-RX_D_END    EQU H'0060'
+RX_D_END    EQU H'005F'
   
   ;;     all pages
 BEACON_INT  EQU H'0070'
@@ -136,7 +136,9 @@ ext_int
   movwf     RX_STATE
   btfsc     STATUS,Z
   goto      ext_int_send_csum
+
 ext_int_next
+  incf      FSR,f
   call      rx_byte
   decfsz    RX_BYTE_CNT,f
   goto      ext_int_next
@@ -148,6 +150,10 @@ ext_int_send_csum
   swapf     RX_CMD,w
   andlw     b'00001111'
   movwf     RX_CMD
+ext_int_wait_ack
+  btfss     GPIO,SCLK
+  goto      ext_int_wait_ack
+  btfss     GPIO,SDAT
   bsf       RX_STATE,complete
   bsf       STATUS,RP0
   movlw     OSC_LOW
@@ -425,7 +431,6 @@ rx_byte_clk_high
 
   movf      INDF,w
   xorwf     RX_CSUM,f
-  incf      FSR,f
   return
 
 rx_byte_next
@@ -451,7 +456,7 @@ rx_send_clk_high
 
   bsf       STATUS,RP0
   bsf       TRISIO,SDAT
-  bcf       STATUS,RP0  
+  bcf       STATUS,RP0
   return
 
 rx_send_next
@@ -792,6 +797,7 @@ seccnt_zero
   ;; this gets called whenever a message was received from ihu
 msg_received
   call      send_ack
+  bcf       RX_STATE,complete
   clrf      RX_STATE
   
 powerdown