lcd.fmt

FPGA 基于PICOBLAZE内核的LCD显示程序,完整,XILINX

                    ;
                    ; The value is displayed in the format      xxx.xxx xxxMHz
                    ;
                    ; However, the most significant 2 digits will be blanked if zero.
                    ;
                    ; registers used s0,s1,s2,s3,s4,s5,s6,s7
                    ;
                    ;
                    ;
  display_3_digits: LOAD s3, 03                         ;3 digits to display
       3digit_loop: FETCH s5, (s2)
                    CALL display_digit
                    SUB s2, 01                          ;decrement digit pointer
                    SUB s3, 01                          ;count digits displayed
                    JUMP NZ, 3digit_loop
                    RETURN
                    ;
     display_digit: ADD s5, 30                          ;convert BCD to ASCII character
                    CALL LCD_write_data
                    RETURN
                    ;
     display_space: LOAD s5, character_space
                    CALL LCD_write_data
                    RETURN
                    ;
                    ;
                    ;
                    ;
                    ;
                    ;**************************************************************************************
                    ; Routines to display hexadecimal values on LCD display
                    ;**************************************************************************************
                    ;
                    ;
                    ; Convert hexadecimal value provided in register s0 into ASCII characters
                    ;
                    ; The value provided must can be any value in the range 00 to FF and will be converted into
                    ; two ASCII characters.
                    ;     The upper nibble will be represented by an ASCII character returned in register s3.
                    ;     The lower nibble will be represented by an ASCII character returned in register s2.
                    ;
                    ; The ASCII representations of '0' to '9' are 30 to 39 hexadecimal which is simply 30 hex
                    ; added to the actual decimal value. The ASCII representations of 'A' to 'F' are 41 to 46
                    ; hexadecimal requiring a further addition of 07 to the 30 already added.
                    ;
                    ; Registers used s0, s2 and s3.
                    ;
 hex_byte_to_ASCII: LOAD s2, s0                         ;remember value supplied
                    SR0 s0                              ;isolate upper nibble
                    SR0 s0
                    SR0 s0
                    SR0 s0
                    CALL hex_to_ASCII                   ;convert
                    LOAD s3, s0                         ;upper nibble value in s3
                    LOAD s0, s2                         ;restore complete value
                    AND s0, 0F                          ;isolate lower nibble
                    CALL hex_to_ASCII                   ;convert
                    LOAD s2, s0                         ;lower nibble value in s2
                    RETURN
                    ;
                    ; Convert hexadecimal value provided in register s0 into ASCII character
                    ;
                    ;Register used s0
                    ;
      hex_to_ASCII: SUB s0, 0A                          ;test if value is in range 0 to 9
                    JUMP C, number_char
                    ADD s0, 07                          ;ASCII char A to F in range 41 to 46
       number_char: ADD s0, 3A                          ;ASCII char 0 to 9 in range 30 to 40
                    RETURN
                    ;
                    ;
                    ; Display the two character HEX value of the register contents 's0' on the LCD
                    ; at the current cursor position.
                    ;
                    ; Registers used s0, s1, s2, s3, s4, s5
                    ;
  display_hex_byte: CALL hex_byte_to_ASCII
                    LOAD s5, s3
                    CALL LCD_write_data
                    LOAD s5, s2
                    CALL LCD_write_data
                    RETURN
                    ;
                    ;
                    ;
                    ; Display the 32-bit value stored in 4 ascending memory locations as an 8 character
                    ; HEX value at the current cursor position. Register s7 must contain the memory
                    ; location of the most significant byte (which is also the highest address).
                    ;
                    ; Registers used s0, s1, s2, s3, s4, s5, s6, s7
                    ;
display_hex_32_bit: LOAD s6, 04                         ;4 bytes to display
       disp32_loop: FETCH s0, (s7)                      ;read byte
                    CALL display_hex_byte               ;display byte
                    SUB s7, 01                          ;decrement pointer
                    SUB s6, 01                          ;count bytes displayed
                    RETURN Z
                    JUMP disp32_loop
                    ;
                    ;
                    ;**************************************************************************************
                    ;LCD text messages
                    ;**************************************************************************************
                    ;
                    ;
                    ;Display 'Frequency' on LCD at current cursor position
                    ;
    disp_Frequency: LOAD s5, character_F
                    CALL LCD_write_data
                    LOAD s5, character_r
                    CALL LCD_write_data
                    LOAD s5, character_e
                    CALL LCD_write_data
                    LOAD s5, character_q
                    CALL LCD_write_data
                    LOAD s5, character_u
                    CALL LCD_write_data
                    LOAD s5, character_e
                    CALL LCD_write_data
                    LOAD s5, character_n
                    CALL LCD_write_data
                    LOAD s5, character_c
                    CALL LCD_write_data
                    LOAD s5, character_y
                    CALL LCD_write_data
                    RETURN
                    ;
                    ;Display 'Generator' on LCD at current cursor position
                    ;
    disp_Generator: LOAD s5, character_G
                    CALL LCD_write_data
                    LOAD s5, character_e
                    CALL LCD_write_data
                    LOAD s5, character_n
                    CALL LCD_write_data
                    LOAD s5, character_e
                    CALL LCD_write_data
                    LOAD s5, character_r
                    CALL LCD_write_data
                    LOAD s5, character_a
                    CALL LCD_write_data
                    LOAD s5, character_t
                    CALL LCD_write_data
                    LOAD s5, character_o
                    CALL LCD_write_data
                    LOAD s5, character_r
                    CALL LCD_write_data
                    CALL display_space
                    LOAD s5, character_v
                    CALL LCD_write_data
                    LOAD s5, character_1
                    CALL LCD_write_data
                    LOAD s5, character_stop
                    CALL LCD_write_data
                    LOAD s5, character_2
                    CALL LCD_write_data
                    RETURN
                    ;
                    ;
                    ;
                    ;
                    ;**************************************************************************************
                    ;Software delay routines
                    ;**************************************************************************************
                    ;
                    ;
                    ;
                    ;Delay of 1us.
                    ;
                    ;Constant value defines reflects the clock applied to KCPSM3. Every instruction
                    ;executes in 2 clock cycles making the calculation highly predictable. The '6' in
                    ;the following equation even allows for 'CALL delay_1us' instruction in the initiating code.
                    ;
                    ; delay_1us_constant =  (clock_rate - 6)/4       Where 'clock_rate' is in MHz
                    ;
                    ;Registers used s0
                    ;
         delay_1us: LOAD s0, delay_1us_constant
          wait_1us: SUB s0, 01
                    JUMP NZ, wait_1us
                    RETURN
                    ;
                    ;Delay of 40us.
                    ;
                    ;Registers used s0, s1
                    ;
        delay_40us: LOAD s1, 28                         ;40 x 1us = 40us
         wait_40us: CALL delay_1us
                    SUB s1, 01
                    JUMP NZ, wait_40us
                    RETURN
                    ;
                    ;
                    ;Delay of 1ms.
                    ;
                    ;Registers used s0, s1, s2
                    ;
         delay_1ms: LOAD s2, 19                         ;25 x 40us = 1ms
          wait_1ms: CALL delay_40us
                    SUB s2, 01
                    JUMP NZ, wait_1ms